The Original CZ Forum

GENERAL => Ammo Questions and Handloading Techniques => Topic started by: outdoor_guy on July 21, 2012, 11:23:00 PM

Title: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 21, 2012, 11:23:00 PM
I've been handloading for awhile now, about 7000 rounds behind me, various pistol calibers and some rifle as well.
I've loaded about 2000 9mm, and fired most of them without issue.  Most of these were in my old SR9c, a carbine, and a Taurus which I now wish I hadn't sold.
I had run some of my reloads through my CZ 75b (it's relatively new, maybe only 3-400 rounds), but none of the RNFP reloads, which had shot fine in all the above, previously.  I was loading them between 1.125 and 1.135, depending on how warm, but nothing too hot. 
I took a couple of boxes of these to the range with me yesterday (1.125's) and promptly jammed my CZ on the first feed.  Managed to get it closed, cycled a couple, jammed again, and I gave up and went home.
Did some experimenting last night (made some dummies and pulled the barrel), and it turns out I have to load them around 1.060-1.070 to get them to sit properly in the chamber. 
Has anyone else had this problem? 
I see a few random postings in THR and similar, but most got their 75b to feed at about 1.115, which I'd be fine with.
The lowest published load I found was for 1.090, which makes me really skittish about loading down at 1.060.
I know I can load them shy, powder-wise, but the whole thing feels like a kludge to me.
I'm wondering if I've got a barrel that's not quite reamed fully?

I took out some S&B 124's (RN) last night too, with my barrel removed, and some of those wouldn't seat cleanly either.

Thoughts, ideas?

Thanks,

-pete


Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 22, 2012, 12:06:29 AM
Pete, Welcome to the forum.  Sorry you're having some problems,  but we should be able to help.
First, the CZ (and XD) have shorter chambers than many other pistols,  This chamber shortness also is credited for CZ's accuracy.
This usually shows up when loading "FT" and  "HP" bullets, especially with conical noses.  The straight & long bullet sidewall makes contact with the cone/rifling at shorter lengths than many pistols.  Bullets with a traditional ogive nose shape, usually run smoothly at common lengths.  "Wobbly" has excellent pictures and cartoons that illustrate what happens--do a search..
Here's one of his I had: 
(https://lh6.googleusercontent.com/-B6fJ8jy-yf4/TeCMgDkFLnI/AAAAAAAAAhs/7ppH3ti-z-w/s640/Rifling%2520Depth.jpg)

The "FIX":  always test new bullets for chamber fit. Use a "spent" "unsized" case that the new bullet  can be inserted into slightly "by hand"---just far enough to hold it in place.  With the bbl removed, push this dummy round into the chamber slowly but firmly until it seats fully on the case mouth.  Turn the bbl up and "gently" pull the dummy rd out and measure it.  Do this with several cases and bullets to get a consistent measurement.
This length IS TOUCHING THE RIFLING/CONE.   Subtract .015" from that length and you have the maximum oal that will reliably feed in THAT pistol with "THAT" particular brand and type of bullet.   This is actually easy to do and only takes a few minutes..
  Find load data for that type and weight of bullet at that max usable oal or shorter.


I can't explain the S&B RN problem without actually looking at it myself.  I don't shoot/load S&B.
With a NIB CZ, many suggest shooting  500 rds of  115gr FMJ WWB or Federal from Wal-Mart to beak it in and loosen it up .  Rem/UMC has a history of problems with some guns, so I recommend avoiding those until after the gun is broken in.

We also need MORE INFO to maybe add some experience to our suggestions..  1. Bullet Manufacturer, specific nose type (FP-Conical etc), powder,  oal, Load Manual Source.

I'm sure others will add what I may have omitted.

Hope this makes sense  (P.S. I reload for a 9mm 75B--)



Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 22, 2012, 01:07:45 AM
Thanks, I understand the actual contact problem (the ogive shape relative to the short chamber), but where do you get max OAL info for a given bullet?

In my case, these are Montana XTreme 124gr FP: http://xtremebullets.com/plated.htm

I also understand how to figure out my OAL for seating, done a fair amount of that previously, in particular on rifle where it's more critical.
On my .308 I've got my setback down to a couple of thousandths, for example.

I don't think  I've ever seen bullet data published for maximum OAL of a given bullet for feeding, wouldn't this depend on the chamber (such as the short one in the CZ)?

I'm probably missing something here, in terms of how to figure this out, BEFORE I purchase the bullets (typically I mail-order lots of 500 or 1000, the closest reloading place is about a 2-3 hour round trip, and is very spendy).
I'm all ears though, I'd like to avoid this in the future, for now I've got to try and figure out how to re-sell 2000 FP 124 bullets  :o

Thanks for all the info, and more,

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: czkali on July 22, 2012, 01:30:45 AM
+1 to everything 1SOW said (and Wobbly's graphics).
 
What you said "wouldn't this depend on the chamber [barrel]" is exactly the issue -- you get Max OAL for YOUR barrel and YOUR bullet shape (may be different for another type in your barrel) by doing the drop test 1SOW was talking about.
 
I'm loading Berry's 124g 9mm HBRN at 1.140" OAL in my 75B. Using the drop test I found my barrel's physical Max OAL is 1.21" for that HBRN. However we know SAAMI max OAL for 9mm is 1.169" so my OAL is limited by SAAMI max OAL not my barrel's max OAL. Take 1.169" - 0.015" = 1.154" Max OAL for that HBRN in my CZ's barrel.
 
I'm curious did you try to shoot the S&B 124g RNs? It's my understanding S&B ball ammo is what CZs are designed with/for.
 
Hope this helps find the right load parameters for your CZ and bullet. To date my reloads have been flawless in my gun using the drop test method I learned on this forum.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 22, 2012, 02:56:04 AM
Yeah, that's what I thought, it's relative to my chamber/bullet combo.  I've done a fair amount of reading and experimentation reloading so far, and the chamber depth issue seems simple enough.

I guess I figured as long as I stayed on the light-mid range in terms of bullets, I'd be okay in terms of OAL. 
I understand the drop-test, but what I don't understand is how you determine what to order, particularly if you can't buy locally what you can order or vice-versa?   Is there another way to make sure you don't end up with a bunch of bullets you can't load/shoot? 
Is there a secret to getting a sample of various bullets from a manufacturer, in order to set up dummy loads for the drop-test?

I'll definitely be buying only RN in 9mm from here forward, and I'll probably stick to 115's or maybe 124s.

I haven't tried firing the S&B's although I did load up some of the FP's, at 1.06, 1.07 and 1.09, and am hoping to find some time tomorrow to stop by and do a quick test on each.  I loaded them all really light (I typically only load at 50-75% of max anyway, often more like 25% of max, the paper doesn't know), to keep things safe since I've got them seated so far down in the case.
I'm hoping I can load them at 1.09, although I'm not sure how I'll know which really worked.  When I loaded the dummies last night at 1.15 and 1.10, the action "seated" them for me, down to about 1.07-1.08, even though I'd put a pretty heavy taper crimp on them.
I'm assuming that's what happened to my 1.25's as well that I fired Friday, luckily I had them loaded light too...

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 22, 2012, 08:25:40 AM
I'll definitely be buying only RN in 9mm from here forward, and I'll probably stick to 115's or maybe 124s.


Pete -
Welcome aboard!

IMHO, when you say that, you are simply going to the other extreme. That's not what we're saying at all.

It's true, most all RN fit the CZ chamber better than other shapes, but that's no reason to stop all other choices. Sometimes you want a nice clean hole in paper targets that a FP will deliver. At those times you simply have to be more careful in your bullet selection.

How can you best choose a bullet new to you? Well, the only way I know is to ask here. Collectively, we've ordered most all the commonly available bullets... and yes, stumbled and fumbled our way to a useful OAL with most all of them. So, what bullet shape - weight would you like to order?

We're here to help!   ;)
Title: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: czkali on July 22, 2012, 12:02:53 PM
If you take out your barrel the loaded round should be able to drop in and out of your barrel on its own. I'm not sure what you mean by "seated". Also you don't want a heavy taper crimp, that will only serve to increase pressure. If you search the forum for taper crimp you'll find some good info on that too.

I called Berry's and ordered some free samples when I was working up loads for my .40 75B. They wont send you a ton of course, just enough to test with and wet your appetite. They give great service and to date with my limited needs I've only bought Berry's bullets.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: vincentperil on July 22, 2012, 01:00:16 PM
Hi Outdoor ! If you think your chamber is short, you'd be scared about mine. I load 124g Berry's hp at 1.018 OAL. with good accuracy and soft recoil. I too stay on the moderate side of the powder load as I know my OAL is shorter than published loads.
Hope this helps
Vincent
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 22, 2012, 03:31:43 PM
Thanks for all the useful replies, I think I've got somewhere to start now. 
Given what others had to seat their bullets down at (OAL), I'll test my "short" loads and if they feed, I'll just load some specific rounds for the CZ and label as such.
For now I've got to use up my lot of FP bullets, and some HPs I have for 9mm as well, but if I decide to go with something other than RN for 9 in the future, I'll definitely check with everyone here as to which they've had success with (without having to seat so close to the minimum OAL).

I should've started here, it just never occurred to me that my CZ would have given me this type of grief, if you can call it that.  I think my reloading experience to-date has been a little too smooth, for the most part.  :o

How about having a sticky with the brands/weights/shapes of bullets that work with a standard OAL?  Is this too much of an endorsement?
It sure would be handy, and could even be added to the "bullets" sticky?

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 22, 2012, 06:25:15 PM
To my knowledge Berry Mfg, Precision Delta, and Winchester 115 and 124gr RN can be fitted to the SAAMI max of 1.169".

But finding out the exact maximum is much easier than making a list. So much easier that I simply do it for all bullets. At most it takes 3 minutes, once you get accustomed to the drill. The instructions are found in THIS THREAD (http://www.czfirearms.us/index.php?topic=34225.msg188816#msg188816).


Hope this helps!  ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 22, 2012, 06:34:41 PM
RN is pretty easy, I think most of them will fit when loaded to standard lengths.
How about FP though? 
For example, I know my XTreme bullets don't fit, given minimum OAL specs in published load data. 
At least that's true in my 75b, I guess others' barrels may differ slightly, but I'd guess it's going to be very close in anyone's barrel, regardless.

Like I said, I've done this type of test in my loading for rifle, given the tolerances, but I'd never run into anything like this in pistol, in about 6500+ rounds loaded.  I'd tested a couple of my .40 pistols way back when I started, and found them to have fairly long chambers and tolerant of pretty much any FP loads.

This is the data, that if someone browses here first, prevents them from buying 2000+ FP's that are marginal, like me :o

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Bret on July 22, 2012, 08:31:50 PM
This chamber shortness also is credited for CZ's accuracy.
That's what they say and in theory it should be true.  However, my 9mm Witness Classic (all steel small frame) and my 9x23 Witness Match, both of which have leades that are so far out the cartridge length allowed by the magazine is the limiting factor, are more accurate than my 9mm CZ75 SA.  In my opinion, the short CZ leade isn't worth it.  However, it's there and we just have to deal with it.  Once you know what to do it really isn't that much trouble.  As has already been pointed out, you just have to be careful with bullet selection.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 22, 2012, 08:55:08 PM
Quote
Given what others had to seat their bullets down at (OAL), I'll test my "short" loads and if they feed, I'll just load some specific rounds for the CZ and label as such.
If you do the "push test" first, you'll KNOW if they feed or not.

Actually, if you have several 9mm pistols, they will ALL accept and shoot the ones loaded for the shortest chamber---in your case, the CZ.

Let us know how it works out.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 23, 2012, 09:49:41 PM
Went to the range today, with my 1.06, 1.07, and 1.09 XTreme 124gr FP loads (the ones I have 2000 of, or about 1950 now  :o).

The 1.06 were the only ones that really functioned well, and even then they were hit-miss, maybe 1 out of every 5 failed to chamber properly.

I guess I'm stuck with going even shorter (some here mentioned loading down around 1.02), and reducing my loads a bit more.  At this point I'm off the load-data chart, the shortest I could find anywhere was 1.07, but even my 1.06's looked okay after firing, no flattened primers or anything obvious anyway.

I'm thinking about getting my chamber reamed a bit, but I'll probably start that discussion in another thread.

Thanks again for all the info, and listening to my woes with my FP bullets,

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 23, 2012, 10:17:12 PM
Mr Outdoor -

There's a LOT of reasons cartridges won't chamber correctly with 9mm. It's actually one of the harder cartridges to load. So please don't confuse "popular" cartridge with "easy to reload" cartridge.

Since there are multiple reasons ("variables" in mathematical speak), guessing at the OAL is not helping you in this situation. With 9mm you need to actually KNOW your max OAL. That way, if your cartridges are being constructed shorter than the "max" and you are still having issues, then you can positively discount the OAL as having any effect on the issue and directly pursue the real cause, having ruled out OAL as a cause.

I'm not trying to make light of your situation here, but in the time it took you write your last post, you could have found the correct OAL for your bullet-barrel combination and been moving toward a solution. That's the beauty of the "scientific method". You move from fact to fact, building knowledge each step of the way.

Sorry my friend, but since it's your barrel and your bullet, there's not really a way anyone here can help if you don't want give us some hard measurement numbers.

All the best!   ;)


Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 23, 2012, 10:38:55 PM
I have some RN bullets loaded out at 1.135, these chamber just fine, either with the drop-test, or from the clip.

My XTreme FP (conical shaped to the FP), are the only bullets I've had a problem with in my 75b, Zero 124s (RN), Winchester 124s (HP), all have worked fine, loaded in the 1.25-1.35 OAL range (this is my regular OAL load range).

If I dummy load my Xtreme FP bullets at 1.00, they chamber just fine, again either using the drop test or the clip (I made 3 of this length).
Somewhere around 1.04-1.05 seems to be workable, I'm just not very comfortable loading this short.

Mostly I wish I hadn't bought the FP/conical-shaped 124gr Montana XTreme bullets.  Even though they were cheap, they're turning out to be more of a headache than the value has even come close to offsetting. 
They do shoot fine (loaded at 1.125-1.135) in my 9mm carbine, and worked fine in the Taurus I sold recently as well.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 23, 2012, 11:01:47 PM
Pete -

My friend, I'd truly like to help you, but to do so we need you to take a chamber measurement using your bullet in your barrel.

Anything less is guessing. And you sir, are guessing.

And yes it's true, not every bullet was meant to be reloaded in every barrel. The measurements you make may tell us you have bought such a bullet. But the purchase is now a "done deal". The money is gone. Putting off the measurement will not make the bullet fit better or get you your money back. At this point you have nothing else to loose and yet everything to gain.

So why, my friend, are you procrastinating?

Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 23, 2012, 11:11:36 PM
I have some RN bullets loaded out at 1.135, these chamber just fine, either with the drop-test, or from the clip.  I believe Wobbly's excellent graphic (above) showed my situation pretty well.

My XTreme FP (conical shaped to the FP), are the only bullets I've had a problem with in my 75b, Zero 124s (RN), Winchester 124s (HP), all have worked fine, loaded in the 1.25-1.35 OAL range (this is my regular OAL load range).

If I dummy load my Xtreme FP bullets at 1.00, they chamber just fine, again either using the drop test or the clip (I made 3 of this length).
Somewhere around 1.04-1.05 seems to be workable, I'm just not very comfortable loading this short.

Mostly I wish I hadn't bought the FP/conical-shaped 124gr Montana XTreme bullets.  Even though they were cheap, they're turning out to be more of a headache than the value has even come close to offsetting. 
They do shoot fine (loaded at 1.125-1.135) in my 9mm carbine, and worked fine in the Taurus I sold recently as well.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 23, 2012, 11:33:52 PM
And yes it's true, not every bullet was meant to be reloaded in every barrel. The measurements you make may tell us you have bought such a bullet. But the purchase is now a "done deal". The money is gone. Putting off the measurement will not make the bullet fit better or get you your money back. At this point you have nothing else to loose and yet everything to gain.

So why, my friend, are you procrastinating?

I'm not procrastinating, I guess I don't understand what measurement you want then?  I posted that 1.04-1.05 will reliably pass the measurement test you mentioned originally.
I created a number of different sized dummy loads, to test what will feed with my FP ammo, and now know those are <=1.05.

From your first post then, if I subtract .015, that puts me down at 1.025-1.035 for a load that will reliably chamber with the FP bullets in question.

This is the part that concerns me, loading at 1.025, well below any published data I can find.

Would you please clarify how I'm guessing, if this doesn't qualify for the correct measurement? 

Thanks for all your help, even if I seem confused,  :o

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: painter on July 24, 2012, 07:04:21 PM
And yes it's true, not every bullet was meant to be reloaded in every barrel. The measurements you make may tell us you have bought such a bullet. But the purchase is now a "done deal". The money is gone. Putting off the measurement will not make the bullet fit better or get you your money back. At this point you have nothing else to loose and yet everything to gain.

So why, my friend, are you procrastinating?

I'm not procrastinating, I guess I don't understand what measurement you want then?  I posted that 1.04-1.05 will reliably pass the measurement test you mentioned originally.
I created a number of different sized dummy loads, to test what will feed with my FP ammo, and now know those are <=1.05.

From your first post then, if I subtract .015, that puts me down at 1.025-1.035 for a load that will reliably chamber with the FP bullets in question.

This is the part that concerns me, loading at 1.025, well below any published data I can find.

Would you please clarify how I'm guessing, if this doesn't qualify for the correct measurement? 

Thanks for all your help, even if I seem confused,  :o

-pete

Take a spent case from your gun...don't size it.

Put the bullet in question in the case just barely starting it.

Remove the barrel from your pistol and push this dummy round into the chamber as far as it will go.

Take it out and measure it.

Repeat this process until you start getting repeatable numbers.

Subtract .010-.015 from that number and now you have the max oal for that bullet brand and type in your barrel.

You can't just assume that because 1.04 or 1.05 work that that's the number you work from.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 24, 2012, 08:33:48 PM
I'm not procrastinating, I guess I don't understand what measurement you want then? 
Pete -

Welcome back. It's in post #9 of this thread.


I posted that 1.04-1.05 will reliably pass the measurement test you mentioned originally.
With all due respect, if you had asked me about my weight so that you could accurately mix medicine to cure me, and my response was "between 180 and 240 pounds", then you might start to understand our predicament here. In post #15 you said "Somewhere around 1.04-1.05 seems to be workable...." The method I outlined, returns an exact number, precise to 3 decimal places. An exact method that will work EVERY time. Not a mushy dimensional range.

And that's my point. In order to help you we need a number. An exact number. If you'll do the "push test" trial with 10 different bullets, then one number will start to appear over and over. That's the number we need. Then we can start to help you.


From your first post then, if I subtract .015, that puts me down at 1.025-1.035 for a load that will reliably chamber with the FP bullets in question. This is the part that concerns me, loading at 1.025, well below any published data I can find.
? I will not try to deny how you feel about a certain OAL. I have strong feelings and preferences myself. But THAT is not part of this discussion. The focus, first and foremost, has to remain on measuring the max OAL your chamber will allow with that particular bullet.

? To get a safe load for a short OAL is the easiest part of this ordeal. All you have to do is call the powder manufacturer and ask. They have tons of data they do not publish, but will gladly fax or email to you. There are also ways to calculate it. But first, we need a max OAL measurement.  

The ONLY way to get the exact load is to KNOW the exact OAL. Follow?
 

So please, focus like a laser on the maximum OAL your chamber will allow.   ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 24, 2012, 11:34:53 PM
Ok, I didn't do a full ten, but I did test 5-6, and they all came out at about 1.040-1.045.
Using your "subtract .015" method, I loaded a small batch at 1.030 (at 5% less than minimum published charge), and they all pass the plunk test.  Almost all rotate after the test too, so this seems to be about where I'm at with this bullet combo.

I tried calling XTreme awhile ago about some 7.62x39 plated bullets and velocity data, and it was very difficult to get anything from them.  They finally gave me a number of 1500fps, and maybe I could get away with faster velocities, they had heard of others doing so.
I didn't exactly hang up with a warm-fuzzy feeling, or any great data either.
Hopefully it was the person I called, and not indicative of the whole customer-service experience there.

To be honest, I'm not really that particular about how I "feel" about a given OAL, other than some heresay I've read about the shorter OAL.  I am however very wary of loading outside of published data, in this case 0.05 outside of the data, which is where I start to feel nervous about the whole deal.

Hopefully my 1.030 loads will yield clean cycling, plus give me some indication that the pressure is still fine.  I can work up from there, slowly I guess, unless I can get data from the manufacturer as you mention (I prefer this, at least as a starting point).

I think it's the fact I've only been reloading for a couple of years; if I'd been doing this for 20 I probably would have a much better "feel" for the whole margin-of-error factor.  Right now I mostly have what I can read, in reloading manuals and online, and most of it tells me there is very little margin in 9mm, given the case size (which makes perfect sense, from a physics angle).

Thanks again for all your help, hopefully this gives more to go on,

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 25, 2012, 12:39:11 AM
Pete, sounds like you have what you need to 'develop' a load for these bullets.

As you said, I recommend you start low and work up slowly with your  load data.  Load 5-10 at the low end, 5-10 a short step (.1 gr with titegroup) up in the load data, etc..    Make sure those low end loads punch holes in the paper, before you you pull the trigger again----watch for squibs---make sure the action cycles smoothly.

Load data is a "Guide" for loading safe ammunition.  .  It is just loaded "within" SAAMI/CIP size and pressure standards for 9mm.  Eastern European chambers (CZ-XD) are different than German (SIG) chambers.  German chambers may be different than US chambers.  Etc. Etc.  No two are identical.    A LOOONG slender jacketted round nose bullet (what Eastern Euro guns were designed around) will normally load out to SAAMI MAXimum with no problems.   Change from that standard ogive round nose design, and all bets are off.     Bullet NOSE-Shape is usually the biggy.

You may end up really liking that bullet-powder combo.   We're all waiting to hear about how they shoot. 

If you change to a different bullet, DO the Push Test again to check for the MAX oal that will run in that pistol.

 



Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 25, 2012, 01:01:38 PM
Ok, I didn't do a full ten, but I did test 5-6, and they all came out at about 1.040-1.045.
Pete -
Hooray!! Now that's a number we can work with!! Sorry if you feel like I've put you 'through the ringer', but in reloading I prefer exactness.

Using your "subtract .015" method, I loaded a small batch at 1.030 (at 5% less than minimum published charge), and they all pass the plunk test.  Almost all rotate after the test too, so this seems to be about where I'm at with this bullet combo.
? We usually work with novice reloaders, and so the .015" dimension is an allowance that accounts for inconsistent OALs over a group of 50 rounds. You said that you were a long-time reloader, and if you have no trouble holding OALs at very consistent lengths then you may, if you like, shorten up on that number.
? Generally in pistol reloading, the "starting load" is 10% less (or 90% of published). Best accuracy starts to appear around 95% of published. So you are missing your safety factor and your "control" shots to gauge your increase in accuracy by starting at 95%.

I tried calling XTreme awhile ago about some 7.62x39 plated bullets and velocity data, and it was very difficult to get anything from them.  They finally gave me a number of 1500fps, and maybe I could get away with faster velocities, they had heard of others doing so. I didn't exactly hang up with a warm-fuzzy feeling, or any great data either. Hopefully it was the person I called, and not indicative of the whole customer-service experience there.
? If you want to know how much the bullet drops over distance, then call the bullet manufacturer.
? If you want to know load data, then call the powder manufacturer.

You've simply consulted the wrong resource. If you'll call the powder manufacturer, then he'll fill your inbox with enough data to choke a cow.

To be honest, I'm not really that particular about how I "feel" about a given OAL, other than some heresay I've read about the shorter OAL.  I am however very wary of loading outside of published data, in this case 0.05 outside of the data, which is where I start to feel nervous about the whole deal.
That's very reasonable. I respect your caution in this area.

Hopefully my 1.030 loads will yield clean cycling, plus give me some indication that the pressure is still fine.  I can work up from there, slowly I guess, unless I can get data from the manufacturer as you mention (I prefer this, at least as a starting point).
I don't think you're ready to load just yet. Can you please share the name of your powder with us again. Sorry, but I'm following 6 threads on 2 boards and don't want to mess up.

I think it's the fact I've only been reloading for a couple of years; if I'd been doing this for 20 I probably would have a much better "feel" for the whole margin-of-error factor.  Right now I mostly have what I can read, in reloading manuals and online, and most of it tells me there is very little margin in 9mm, given the case size (which makes perfect sense, from a physics angle).
That's correct, and that's the driver for my insistence on exact numbers and lots of details.

All the best.  ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 25, 2012, 01:14:11 PM
[color]

? We usually work with novice reloaders, and so the .015" dimension is an allowance that accounts for inconsistent OALs over a group of 50 rounds. You said that you were a long-time reloader, and if you have no trouble holding OALs at very consistent lengths then you may, if you like, shorten up on that number.
? Generally in pistol reloading, the "starting load" is 10% less (or 90% of published). Best accuracy starts to appear around 95% of published. So you are missing your safety factor and your "control" shots to gauge your increase in accuracy by starting at 95%.

? If you want to know how much the bullet drops over distance, then call the bullet manufacturer.
? If you want to know load data, then call the powder manufacturer.

You've simply consulted the wrong resource. If you'll call the powder manufacturer, then he'll fill your inbox with enough data to choke a cow.

To be honest, I'm not really that particular about how I "feel" about a given OAL, other than some heresay I've read about the shorter OAL.  I am however very wary of loading outside of published data, in this case 0.05 outside of the data, which is where I start to feel nervous about the whole deal.

I don't think you're ready to load just yet. Can you please share the name of your powder with us again. Sorry, but I'm following 6 threads on 2 boards and don't want to mess up.

[/color]

Tried to cut/past the most relevant parts here, to respond to.

To be clear, my 5% less loads are 5% less than the published minimum, for a 1.090 OAL.
I'm loading 3.9gr of TiteGroup, for reference.  Published load minimums are 4.1-4.7, depending on which source you're referencing.

Too late on the "not ready to load", I put together 50 rounds last night at this load, and 1.030.  They all pass the "plunk" test, and most turn in the barrel (a few are very close the rifling and "catch" a bit).  My plan is to test these later today.
Given that I'm under the low-end of the loads for my poweder, I feel pretty safe.

Previously, my 4.2-4.3gr loads were getting "default compressed" by my CZ, I just didn't know this was happening when I was tapping the slide to close it, until I ejected an unspent round. 
A spooky way to test, but the 4.2-4.3 loads didn't seem to show any signs of overpressure, the way I understand them, the cases still fit back into the chamber, and the primers weren't flattened.

One of these days I need to get a chrono (to get a better bead on pressure, etc), but they're not "offically" allowed at either of the ranges I shoot at, but one of them I could get away with it, particularly if I went during a weekday, there's often no one else shooting...

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 26, 2012, 12:16:04 AM
Update:
My 1.030 loads at 3.9 of TG work, at least in terms of feeding ok, and cycling the action.  75 rounds worked fine.
Accuracy suffered significantly though, I was surprised, since prior to this, the CZ was by FAR my most consistently accurate handgun.  It would shoot one ok, then 3-4 low by 2-4 inches (tried different distances, ranging from 7-15 yards), then a good one again, rinse, repeat.
Prior to fiddling with the whole FP bullet mess, I would get 8 or 9 VERY consistent shots at these distances, 1.5-2" groupings at worst, more often along the lines of 1-1.5".
Weird, I'm not sure I see how my accuracy took such a dive, but at least I know it cycles with this load (tossed the brass pretty good, 7-10ft consistently).  No pressure signs on the cases either, everything looked ok.  I'm hoping I was just have a really bad day, I probably should've tried shooting from the bench or something to verify.

I did send Hodgdon's an email asking for load data for the shorter OAL, hopefully they'll have some more insight, and I can maybe load up a bit and see if that's the problem...

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 26, 2012, 01:31:02 AM
Titegroup is a very snappy high pressure powder with a very short load range.  Especially with the short oal, load increases should be in .1 gr increments.
Accuracy may change with load change. 
What "I" would do:  Drop 4.0 grs (weigh the load) into a case and measure from the case mouth to the powder using the depth gage on your mic.   Drop 4.1 grs and measure that.   Compare this to your "bullet seating depth" to make sure the bullet base will be safely ABOVE  the powder level.  Use one of the shortest cases for this check.

If it is, load 5-10 rds at 4.0 grs and 5-10 rds at 4.1.  Try the 4.0 load first,  and watch for signs of pressure including how far it throws the ejected cases compared to regular commercial range ammo.  Shoot slowly & check for accuracy.  If all is good, try the 4.1 gr loads.   
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 26, 2012, 12:47:23 PM
Congrats on finally having some success.

Since you are "very wary of loading outside of published data", may I ask where did you got your load recipe from?

I assure you that the pistol's accuracy did not change with the weather. Your CZ is still the same as it always was. So the variations in accuracy can only come from a limited number of variables...
? Variations in OAL
? Variations in the amount of powder
? Using mixed brass
? Inconsistent primers
? Wrong powder
? Simply a bad personal day at the range

Chase those down and it sounds like you'll have it.   ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 26, 2012, 12:57:39 PM
I get my load data from a combination of two manuals (Speer, Lee) and online data from the powder manufacturers.  I also have some data from bullet manufacturers, such as some of the older Rainier data.

I think my accuracy problems are most likely stemming from the powder quantity, but that's just a guess.  Other variables are addressed below:

I have the same primers (SP have always used CCI), the OAL that's right for my barrel/bullet combination, always used mixed brass, almost always load with TiteGroup for small pistol. 
It could've been simply a bad day at the range, no question. 
I think I'll load up some more FP's at the 1.030 and lower-end of the powder scale and some RN loads at my more regular OAL and previous powder quantity.
This way, I can shoot them side-by-side and if I get really consistent results with RN (regular OAL, standard powder quantity) and inconsistent results with the FP (short OAL, less powder to compensate).  RN loads at 4.2-4.3gr have always given me really accurate results with the CZ.
Hopefully this will yield some answers.

Not sure what I'll do with my zillion FPs if that's the culprit though, other than try carefully loading them up, as suggested, or maybe try and sell them off...

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 26, 2012, 01:33:30 PM
I think I'll load up some more FP's at the 1.030 and lower-end of the powder scale and some RN loads at my more regular OAL and previous powder quantity. This way, I can shoot them side-by-side and if I get really consistent results with RN (regular OAL, standard powder quantity) and inconsistent results with the FP (short OAL, less powder to compensate).  RN loads at 4.2-4.3gr have always given me really accurate results with the CZ. Hopefully this will yield some answers.


You can certainly do that, and you will certainly get results. Unfortunately the results won't mean very much and IMHO would be a very bad basis to choose a bullet on. The problem is that by having mixed brass and no control (that I see) on your powder, you start the "race" with a severe handicap. Then you are going to load 2 different length bullets, which may be from different manufacturers, over different amounts of powder.... Right there are 5 major variables you're not controlling.

That's like me trying to compare my wife to a male pig. Different genus, different gender, different earning potential....  I've only changed 3 variables and yet the uselessness of the comparison should be plainly obvious.


Give us a hint. Exactly what is it you're trying to determine? 

Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 26, 2012, 01:55:29 PM
I don't quite see it the same way.  If I were starting from scratch with the loads/gun, I would definitely see the logic though.

I know it's not 100% scientific, but over the course of several hundred rounds initially in the gun, using the other loads (RN or HP, regular powder charges), I had VERY consistent accuracy.
With the (accidentally) FP bullets loaded over the same powder, but being compressed to the shorter OAL (by the guns' action) I also had excellent accuracy.
Loading to the shorter OAL (1.030), and lower charge (3.9gr), the gun seems to shoot very inconsistently.
Agreed, there are several variables in play, but the 1.030 is somewhat fixed, based on the chamber, and the powder charge is limited unless I hear othwise, or very carefully test some loads with .1 gr difference.

That's what I'm mostly trying to determine, if using the previous combination again it will shoot consistently. 
If so, I'll probably stop messing with the XTreme FP bullets I've got and either sell them, load them for my carbine, or if I hear back from Hodgdon's with additional load-data, load them up a bit and see if they produce consistent results.

I like to fiddle, to an extent (used to be a mechanic, way back), but in general my time at the range is limited and I'd like to enjoy shooting mostly, and not wonder if my latest batch of loads is going to be consistent.
9mm bullets are cheap, and life is short, to summarize  ;D

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 26, 2012, 08:06:15 PM
I don't quite see it the same way.  If I were starting from scratch with the loads/gun, I would definitely see the logic though.

Pete -
Don't look now, but you ARE starting from scratch.  ;D The only things you have nailed down are your OAL for that bullet and your primer.

Best of luck my friend and enjoy safe shooting.

 ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 26, 2012, 09:31:32 PM
Pete, I don't see the benefit in loading up more of previous loads with different bullets for any meaningful comparison.

Choices:  You have the bullets.  You have some experience with that powder.  You can follow thru with your load development in .1 gr steps.  You may find you don't like the bullet-powder combination, or you may find the 9mm Holy Grail.  You won't know until you test the load SAFELY step-by-.1 gr step.

Tightgroup is not a very adaptable/forgiving powder.  You can try Win 231/HP-38,  which is much more adaptable with its much wider load range for your short oal .   

If you aren't comfortable with that bullet's short OAL limitations, I also understand that.  I'm not real happy with very short oals either.  I personally draw the line at 1.09+" oals.   You can switch to a different bullet that will allow longer oals.  Your bullets can probably be sold locally .

Reloading gives choices.  Benefit #1.   



 

   

 



Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 27, 2012, 01:08:26 AM
Can you explain more on the load range of 231/HP38 in 9mm?  I see more or less the same range (about 0.3-0.4 gr between min/max) for both powders, and the pressure min/max is pretty close, although I admit 231 tops out at ~28K with 231 and ~30K with Titegroup, so there's a little more pressure safety on both ends of the loads.
Is that what you mean by "adaptable".

I do play around quite a bit with different powders, but more when loading 357, 44Mag/Spl, and rifle, since there's a HUGE variability there.  The pressure differences loading 44 are enourmous, for the same given velocity, depending on powder selection, as I'm sure you know.

Loading 9mm and 40 I tend to default back to Titegroup for probably 95% of the loads, although I have done some with Longshot, and a few with HP38.

Thanks again, both you in particular.  I know I may seem a little random, but I've actually thought the process through pretty carefully, in terms of my options.  My background is math/physics/engineering, so do ok with that kind of stuff, usually;-]
The problem I have sometimes is not "seeing the forest through woods", which can happen when reloading, I'm learning more and more.  Like anything, experience is worth more than a ton of reading/research.

I did load some of my FP loads at 4.0 tonight (still at 1.030), and some regular RN (also 124gr) at 1.125, mainly so I can see how the accuracy plays out next time I get to the range.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 27, 2012, 05:54:16 PM
Tested some again, this time my FP loads at 4.0, 50 of those, still loaded at 1.030 for proper feeding.
Same deal, not shooting accurately at all.  Had someone else at the range try it, plus I shot from the bench, same deal, all inaccurate.  No signs of overpressure though, at least not in terms of the primers.

My new 124gr RN loads with 4.2gr (same powder, same weight, 1.125 OAL) shot fine though, dead-on as is typical for my CZ. 
I think what I'm finding, more than anything else, is that my CZ doesn't like loads on the really slow side, it seems to prefer mid-hot.

I could push my FP's 0.1 grain more I guess, but I was hoping to hear back from Hodgdon on their load data at 1.030, I sent them a request two days ago.

I think I'm going to make at least a local attempt to sell my 1800 or so of the FP bullets, they're just not worth the "hassle factor", to me anyway, plus even loading the 1.030 as it stands is outside of my comfort range.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 28, 2012, 12:08:18 AM
Load data shows 4.1-4.4 for titegroup with a 1.09" oal with a 124gr jacketed bullet.--a .3gr spread min to ma

On one powder burn rate chart, Titegroup is 12th fastest and Win 231/Hogden HP-38 is 22nd.
When you are near the top of the load data, pressures could spike quite high by going above the listed max.  231 burns a little slower and isn't as "spikey" as TG.  The pressures listed in the data are for loads 'within' the data range.  Loads that are compressed or above the load range will increase beyond the the data pressures listed.  It MAY NOT be a linear increase.  Pressures could skyrocket with a very small increase, depending on the powder.  Slower burning powders typically don't skyrocket when the data is stretched just a little.  This all leads to the comment "Win 231 is a little more forgiving".  I don't use TG.  I know several others who love TG with 124gr.

Using oal to powder load proportions, at 1.03" oals , 4.1 grs of TG is almost the max in the LEE data for your oal.  This also assumes there is some empty space left in the case with that oal.  Your decision to make.

re accuracy:  Most powder loads do tend to be most accurate somewhere above mid-range.  Some powders show big improvements, some not as much.
Most of my shooting is inside 20 yards.  My go-to powder for 124gr loads out to 25yds doesn't 'tighten up' that much with more powder..  The patterns do get some smaller above mid-range loads.  My load is soft and within minute-of-6" steel plate at 25yds. ;D

I wish I could have found 'good news' for you with that powder-bullet combination, but I can't find any.   



 



 
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 28, 2012, 04:33:29 PM
Thank for jogging me on the spike issue and the shorter powders.   I'm pretty clued into this for rifle, but for whatever reason I didn't think of that relative to my 9mm loads, I think mostly because I'm pretty conservative with most of my pistol loads, always making sure I've got plenty of space (longer OALs) and pressures aren't near max.
I think for now I'll just shelve the FP bullets, maybe do some seperate loads for my carbine or something, and shoot RN in my CZ; they're fine seated at reasonable lengths, and accurate at the same, so fooling around with the FPs just doesn't make a whole lot of sense, IMHO.

Thanks again, for all the replies, I've learned quite a bit, plus it's made me think about certain reloading concerns that had only been on the periphery for me previously...

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: loaded on July 29, 2012, 12:20:21 AM
Am I missing something here, I loaded up some dummies with Berry?s hbrn 124gn. And
124gn fp.   The aol of the  hbrn is .620 and the aol of the FP is .532

The difference is .88 so if you load a 124 hbrn  @ 1,137 you have .212 of the bullet in the case, and load a 124 fp 1.051 you have only  .202 of the bullet in the case so how can a shorter oal with a shorter bullet be a problem with the same powder charge say 4gn hp38.

You do have a shorter aol but you still have as much space in the case does this make sense or do I have this all wrong.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 29, 2012, 01:20:36 AM
He's using Titegroup powder and a different bullet.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 29, 2012, 08:38:27 AM
Am I missing something here, I loaded up some dummies with Berry?s hbrn 124gn. And
124gn fp.   The [bullet length]  of the  hbrn is .620 and the aol of the FP is .532

The difference is .88 so if you load a 124 hbrn  @ 1,137 you have .212 of the bullet in the case, and load a 124 fp 1.051 you have only  .202 of the bullet in the case. So how can a shorter oal with a shorter bullet be a problem with the same powder charge say 4gn hp38.

You do have a shorter aol but you still have as much space in the case does this make sense or do I have this all wrong?

Mr Loaded -

Welcome aboard.


Not "wrong" at all, you simply overlooked a very basic fact. Unlike the FP, the RNHB has a "hollow base". Therefore it does not have the flat base of the FP so you can''t compare the 2 bullets side-by-side mathematically without using an "effective bullet length". That is to say, what the RNHB bullet length would be if the hollow portion disappeared. Obviously the "effective" bullet would be much shorter than the physical.

You're thinking the right way, but we have to compare apples-to-apples. You'd get an answer closer to what you expected by comparing the standard Berry 124gr RN to the 124gr Berry FP.

Hope this helps    ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: loaded on July 29, 2012, 10:51:16 AM
Wobbly. thanks that make sense so I have some 124gn fbhp so I should be able to compare the two
right.  The HP oal is 563,  FP oal is 532 both have flat bottoms.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 29, 2012, 01:58:41 PM
My 124 FPs (the ones in question) are .510, and my RN 124 are .588. 
I feel pretty comfortable seating my RN at 1.125 or so, which translates down to about 1.047 on the FP, or thereabouts.  That's close to my 1.030, I must admit.

As mentioned, they seat and function at 1.030, with 4.0 grains of TG. I might try some HP38, just to see if I can bump into the mid-range and get my accuracy back, or I might sell 'em, I'm still debating.

The whole RN/FP actual depth relative to the powder/case bottom is very interesting though.  I've often pondered this, given that the OAL isn't really even remotely consistent in terms of providing a normalized seating depth. 
I wish more bullet manufacturers would publish clear and comprehensive data here, since they are the one's who know *exactly* when they're bumping into pressure tolerances, in terms of case volume. 
We're sort of "guessing", based on known good published data and bullet lenghts relative to volume.  Unless I'm missing something?

I'm really glad I started loading .40 first, a couple of years ago, it's still a small case, but not nearly as close tolerances as 9mm, in terms of volume.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 29, 2012, 02:29:39 PM
Wobbly. thanks that make sense so I have some 124gn fbhp so I should be able to compare the two
right.  The HP oal is 563,  FP oal is 532 both have flat bottoms.


I understand that the newer Berry 124gr FP and HBFP now share a very similar ogive shapes, resulting in identical "max OAL" readings from a "push test". The older versions were completely different. So my answer depends on which bullet version you have!!

If both your bullets are the newer versions, then in theory, the lead displaced by the "hollow" is added onto the sides. When comparing 2 cartridges constructed with each of these bullets at same OAL, this makes the case volume under the bullet also equal. Therefore, one could also surmise that given the same powder load, the chamber pressure is the also same for both cartridges. Any difference in bullet performance would then be due to the drag created by having the longer sides of the HB bullet contact more of the barrel.

Details. Details.  ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 29, 2012, 09:33:49 PM
Along the lines of my previous comment.
What would really be interesting is a table that shows:
volume displacement(cu/in?)/.01 in. OAL of a seated bullet (this assumes a specific caliber, such as 9mm).

This way, if you had known combinations that were good (say Berry FP for example) at a given charge, you'd know the remaining case volume for that bullet at a given OAL.
From there, it's a simple ratio calculation to determine if your powder/OAL combination is in the safe volume margin, given the displacment/length table for your particular bullet(s).

One could probably build these  up, by seating to known given good lengths, with no primer, and back-filling the cases with water.  The water wouldn't be the same, volume-wise, but as long as you were comparing a known good combination with water and your case with water, you could extrapolate the data pretty easily (spreadsheets are handy for this type of thing  ;D).

Just a thought, I'm surprised something like this doesn't exist, or maybe it does and I'm just not "in the know"?
It sure takes all the OAL "guesswork" out of the equation, you know for certain if you're in/out of safe maximums.

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 29, 2012, 11:42:08 PM
The 9mm case is straight-wall but tapered top to bottom.  The volume would change constantly per .01" as you went deeper into the case.
Every headstamp will also have slightly different internal volumes and lengths. At a given oal, the internal distance from the primer hole to the base of the bullet would be moderately consistent.
It might still provide a "guide" though.

Maybe you could use a syringe to measure and find the total case volume using water and figure in a rough allowance/distance for the taper.
Easy for me to "guess".  ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on July 30, 2012, 01:02:56 AM
Yeah, the taper had occurred to me, but bullet manufacturers could take this into account, it's not like it's rocket-science  ;D

If you look at the typical (from SAAMI measurements) 9mm cartridge, it's got a volume of 0.2522 cu/in. 
If you look at the volume difference between my 124gr RN and my 124gr FP bullets in question, it's .0309. 

The delta is roughly 10% of the total volume, to me this sounds like a signficant "guess" when it comes to seating the bullet?
I don't have the data on what threshold causes pressure-spikes, roughly, but I'm guessing the delta is far less than 10%, between "totally safe" and "really marginal" to use two totally unqualified terms, but I think it gets the point across.

The more I think about it, I wonder why this isn't used as the standard, the delta between your bullet length and seating.  This would allow a MUCH more accurate case volume result, which is really all we're shooting for here, volumes >= a given threshold, correct?

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: 1SOW on July 30, 2012, 01:49:43 AM
Pete, my "guess" comment was about "how to use your idea", not on bullet seating depth.
Although,  I have successfully used "distance above the powder to get a rough starting OAL with same weight and type bullets, with the same powder with light loads.

I think there are a LOT of variables at work here:
Powder type: large volume  (light weight) flake like unique, vs low volume (and very heavy) small ball-like AA5.  (I can drop almost 3 loads in one 9mm case)
9mm has the widest variations of case dimension,  thickness and resulting internal volume.
Reloader Sizing differences exist resulting in the pronounced "coke-bottle shape", to almost flat sides.  This recountours the cases' tapered sides.

To me, it seems it would be less than precise, or at least very complicated,  to have a  formula for oal and seating depth.




 

 
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 30, 2012, 10:28:49 PM
Will that be enough of the bullet in the case ?


All I can say is that my bullets don't fall out onto the floor, and usually shoot fairly good. You can load any length you want between 1.140 and 1.075". I suggest you try 4 or 5 different lengths between those 2 and see if you can tell a difference. That's the only way to answer your question.

 ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on July 31, 2012, 07:57:40 PM
The pressure will rise dramatically with .010" increments in 9mm.  I'd highly suggest simply making up 5 or 6 test cartridges (no primer; no powder) and manually dropping the slide on the mag over and over. Start at 1.140, then you can shorten them .010 and try it again. With RN you'll not see any difference.


If you must use powder, then you'll want to use a very docile load like 4.1 or 4.2gr of Win231. And don't mistake having enough powder to cycle the gun's action for "feeding good". One is a power issue; one is a mag-bullet-chamber physical alignment issue.

Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on August 02, 2012, 07:37:06 PM
Ok I make up some no primers or powder, I found out that my Cz75 with the 9mm efk fire dragon
will not take the FP's  RN 100% . Now my BHP just eats them up. Looks like RN only for the EFK.


So may I ask what max OAL the bullet push test yielded for your bullet in your barrel? FPRN do seem to be the worst offenders in any "tight chamber", so i don't doubt it's short.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on August 03, 2012, 12:10:27 PM
Well on the EFK berrel it was 1.160-015= 1.145 and the BHP was at 1.145-.015=1.130.  That EFK
chamber is so tight I'm staying with RN only. The FP work great in the BHP.

Either I don't understand, or you got a typo. The number you quote on the EFK is longer than the BHP.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on August 03, 2012, 07:31:13 PM
That won't help without a look at your bullet too.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: outdoor_guy on August 03, 2012, 10:18:16 PM
Geez, I'm no feed expert, but I'd say your chamber mouth needs to be chamfered a little.  Even with RN bullets I could see there being a potential problem, if things weren't just *exactly* right during the feed process.

BTW: Where'd you get your EFK barrel?

-pete
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on August 04, 2012, 03:53:19 PM
Ok I make up some no primers or powder, I found out that my Cz75 with the 9mm efk fire dragon
will not take the FP'  RN 100% . Now my BHP just eats them up. Looks like RN only for the EFK.


Your communication is so unclear and your needs so specific that I highly suggest you get your own thread.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: sixgunal on January 31, 2019, 04:40:12 PM
I know this is an older forum but here's my 2 cents.

  I have been reloading Bayou Bullet 135grain RN's @ 1.135" for my CZ Shadow 2 which chamber and shoot excellent. I recently bought a few Berry's bullet 135 RN & 147 FP to try. The Berry's 135 RN can be loaded a little longer @ 1.150 with no issues.
 Unfortunately the Berry's 147's would have to loaded @ 1.04 to chamber properly so I will probably save those to try in one of my other 9's later.

Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Wobbly on January 31, 2019, 04:49:42 PM
Unfortunately the Berry's 147's would have to loaded @ 1.04 to chamber properly so I will probably save those to try in one of my other 9's later.

That is not the Max OAL we have found for the Berry Mfg 147gr RN.

Besides, I highly doubt any 147gr can be loaded to such a short OAL. Did you really mean 1.140" ?

 ;)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: IDescribe on January 31, 2019, 08:07:18 PM
(http://paulberetta.com/images/external/forums/zombie%20thread.jpg)
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: Radom on February 06, 2019, 02:29:57 PM
Time to Confuse the Issue:

Based on skimming this thread, with no real insight at all, I suggest that the SWC concept is "better" than the RN-FP concept, precisely because it does not engage the rifling until the bullet leaves the case and the pressure drops. 

I only mention this because I have seen many people suggest that RN-FP and SWC are the "same thing/different terms."  To be fair, I haven't seen that claim on this forum.
Title: Re: 124 RNFP, anyone else have issues with OAL in a 75b?
Post by: CzechnoWizard on February 23, 2019, 10:41:17 AM
I use berrys flat point (truncated cone, not RNfp) with great results in several cz 75 variants
124g HB FP TP
LOAD AT 1.060 oal
I was running 5.5g cfe pistol (near max but not +p) but tired of the long ejection distances. No issue with brass life, flattened primers etc but tossing empty too far.
Recently backed off to about 5.2g and seems to be equally effective on steel knockdowns but more controlled ejection.
The HB bullet is longer, so it already intrudes into powder space more than a normal fp and considerably more than a RN.
I share this to say - my experience is that you will not have pressure problems caused by seating at 1.060 unless you are trying to make 9mm major or some such already risky thing. 1.060 is correct with 124 fp