New reloader seating depth question

[LarryBoy]

Just picked up a new Dillon Square Deal B and diving into all the info out there. Have a question on seating depth. I preformed a push test to determine the max cartridge length of 1.180. I then subtract .015 to come up with a maximum OAL of 1.165. I then subtracted the OAL from the bullet length and case length to come up with a seating depth of .169. Is this correct and if so do I need to seat deeper? I think I read it should be around .200. Thanks for the help I'm sure I will have a lot more questions to follow

Firearm
? My CZ pistol/rifle model is:  [ SP-01 ]
? The caliber of my CZ is:  [9x19 Luger]
? My CZ has the following changes:  [Comp Hammer, 13#Recoil Spring, 85 Combat Trigger,]
? I use this CZ in the following ways:  [USPSA competition, general plinking]
? I want ammo accurate at:  [25 feet ]

Components
? I've been reloading for months/years:  [Just started, 0 rounds completed]
? Fully describe the maker, weight, and type bullet:  [ Berry 124gr RN]
? Powder (brand name and load range):  [HP-38]
? Primer:  [CCI]

? Reloading Equipment
? Press brand and type:  [Dillon Square Deal]

[IDescribe]

I think I read it should be around .200.

I don't know if should is exactly the right word, but yeah, give that a go.  Personally, if a 124gr RN bullet will push and plunk 1.17 or longer, I will arbitrarily pick 1.16, 1.155, or 1.15 and go, without even considering its depth.

That said, a lot of the good fellas in this forum will do exactly what you're describing and knock it down to 1.14 or even 1.13, which I think is probably around .200.  I don't know that anyone knows with certainty that the advantage is a result of depth, and .200 is the magic number, or if the bullet just likes the extra jump to the rifling, but either way, I think a number of the guys have arrived at this slightly shorter than necessary OAL being good for accuracy in one way or another, so there's no reason not to check it out. 

[Wobbly]

Larry -

Welcome Aboard !!

? It was probably my post you read with the 0.200" quote. Actually, I believe that was corrected by ID and the seating depth goes up to around 0.300" on some brass. Either way, I didn't mean to infer that was a "magic" number that must be met.

What you're aiming for is a range of insertion that will hold the bullet securely AND allow time for pressure to build before the bullet is released. Of course you need to be using a brand of brass that supports your depth decision.

You see, some of this is science and some of this is "the art" of reloading. For most 124/125gr RN I use numbers in the 1.130 to 1.140" range. You won't be sorry with that. But that only meets the barrel's requirement.

? We don't know what load data you'll be using, but the published load will become your Min OAL. (This is why we asked for this.) So you'll be working between the 1.165" of the barrel and the load data. See the cartoon below...



? HP-38 may show up in some manuals as "Winchester 231". They are exactly the same powder and you need to know that when you start looking at manuals. Most manuals list one or the other, but not both.

This is an excellent powder that will be very safe for you to use due to its wide load range. So you can make some novice errors and still be around to talk about it. It will be slightly sooty at the lower end, but cleans up nicely in the optimal load range and is very easy to "read". Excellent first choice.

? In the interim, you'll need to spend some time setting up your Belling at the (#2) Powder Die position, and the (#4) Taper Crimp setting on the last die position. If you need help, then we can assist.


CAUTIONARY NOTE: Your choice of Comp Hammer and CCI primers may not play well together. I predict a 1-5% failure-to-fire rate if your Comp Hammer is accompanied by a reduced hammer spring. If you can find some Federal #100 SPP today while the shops are open you'll be a lot better off.

All the best.   


PS. I want you to be collecting a single 38 Spcl brass case, a 6' length of clean vinyl tubing, and a ~1/2" dia countersink cutter today while you're out.

[painter]

FWIW, I have no issues with Win primers with a stock firing pin and a 13lb hammer spring in my 85 Combat..

I had no issues with CCI either, but the Win's were more available, so I switched to them.

[Wobbly]

Without complicating things too much.... Since you're a competition shooter, here's some general reloading info so that you can understand more of the "art"....

1.169" is the SAAMI max for 9x19 Luger. That number affects numerous things. The major one you'll be concerned with is "will the cartridges jam in the magazine making my competition efforts frustrating ?"

So what is the longest cartridge you can optimally use in competition ?

? All reloading presses vary in their OAL output, so you have to aim at building cartridges slightly shorter so that when one gets built to the longest extreme it will still work perfectly. IOW, if 1.169" is the maximum, then the longest cartridge we should plan on building is 1.160" !! In that way, if one slips out at 1.166" (+0.006") it won't jam the gun in the middle of competition. Follow ?

? Round nose bullets are fairly slick on the meplat, and without any protrusions or sharp edges feed very well with no hangups. But very soon in your competitive career you may wish to try some HP bullets. The most popular, 124gr Zero and 124gr Precision Delta, have sharp edges on the meplat that could hang up inside of the mag, jam the feed mechanism, and have a predictable effect on your score. That's not good. So when we load HP bullets we want to use a shorter OAL, say something like 1.130 to 1.140", to prevent these magazine jams. The greater clearance inside the mag simply lessens the chance of any magazine feed issues.


All this because in competition preventing errors is just as important as improving shot placement, because both contribute to the making of good scores.

 

[Wobbly]

FWIW, I have no issues with Win primers with a stock firing pin and a 13lb hammer spring in my 85 Combat..

I had no issues with CCI either, but the Win's were more available, so I switched to them.

CCI are recognized as the "hardest" or thickest cup, while Federal are recognized as the "softest" or thinnest cup. Winchester and Remington fall between those 2 extremes.

With Larry being a new reloader, there will be a certain percentage of not-fully-seated primers. So with a CCI primer, it's going to be hard to tell if it's the hammer or the reloading technique that need improvement when the FTF's start occurring.

Agreed. Winchester WSP would be a good move.

 

[painter]

Seating primers on a Rockchucker pretty much assures the operator that they're in all the way.

[IDescribe]

With a 13# main spring in my Shadow Line, many thousands of CCI went bang every time EXCEPT for two very early on, both from the same loading session, both of which went bang on a second strike, suggesting I hadn't seated them fully.  My bad, not the main spring or primers'.

Currently, I use a 10.5# main spring.  Winchesters (and obviously Federal) go bang every time.  My preference is Winchester.

If you go down to the 7# main spring, you're going to want to use Federal only.

[LarryBoy]

Thanks for all the info. I'm out and about today so I'm going to pick up some Frderal primers also picking up a Lyman manual. Hopefully get to load this evening or tomorrow.

[Wobbly]

Thanks for all the info. I'm out and about today so I'm going to pick up some Federal primers also picking up a Lyman manual.

? Lyman comes hard backed and paperback. Get one that will last.
? Federal or Winchester. You can use the CCI on your practice ammo; it won't go to waste.
? Buying a Lube Pad (~$15) is cheap and could be very helpful.

Hopefully get to load this evening or tomorrow.

? If you are going to do that, be sure and buy an RCBS kinetic hammer so you can dis-assemble your first rounds !! 
? You're a long way from reloading just yet, friend.

 

[LarryBoy]

Ok I picked up the Lyman 50th Edition. Looking at the 9mm data for 124 grain. The only data they give for that weight is 124 gr Jacketed Hp. Would that be the data I work off of using the Berry,s 124 gr RN? Or am I missing something?

Don't worry Wobbly, I know I'm a long way from reloading. Just was going to tinker with the machine to start getting familiar with her. I'm taking it slow and easy.

[painter]

If you're using a RN bullet, then your OAL will need to be longer.

Starting load will keep you safe.

You might want to compare bullet lengths in 1SOW's bullet length thread in this forum.

[LarryBoy]

Thanks Painter. I will use a OAL of 1.135 and work off of a suggested starting grain of 3.8 with a max load grain of 4.5 using data of 231 powder which is the same as HP-38. Does that look correct?

[painter]

With a RN bullet the load window shifts. You can no longer use the same max load at the published OAL due to the difference in bullet length.

It really is all about seating depth. That's what determines pressure for a given bullet weight.

This thread.... http://www.czfirearms.us/index.php?topic=62657.msg415616#msg415616 ...will give you enough info to adjust your OAL for the bullet length  difference.

[IDescribe]

While that's a great manual, http://www.hodgdonreloading.com/data/pistol has data for Berry's 124gr RN and HP-38, so wouldn't that be better data to direct him toward in that it's an exact match?

OAL 1.15 and 3.9gr - 4.4gr. 

The OAL difference of .015 to get to his OAL of 1.135 doesn't even need a charge weight reduction.  He could use that data straight.

And if you really wanted to do a charge weight reduction anyway, it would only be .1gr.