Baldrage's reloading log

[IDescribe]

I THINK Wobbly is saying he'd be inclined to use 1.100 or 1.110 instead of Hodgdon's OAL of 1.090.  I don't believe he's suggesting you shorten the OAL of 1.125 that you have been using down to 1.100 or 1.110.  You're at a seating depth of .224 already at the 1.125 you have been using.

Or did I misread something? 


ALSO, in your calculations, just use a case length of .75 inches for ALL cases.   SAAMI standards say a 9mm Luger case should be .754, but cases can range anywhere from .730 up to .760. Most are actually shorter than .750, even when they're new.  One of the main reasons we look at seating depth, and why you're looking at it here, is because when the bullet is seated, what space is left over in the case is a combustion chamber, and the initial size of the combustion chamber affects pressure.  The deeper the bullet is seated, the smaller the initial combustion chamber, and the higher the peak pressure will be.  The size of that combustion chamber is unaffected by differences in case length.   If you have two cases, where one is .740 and the other is .750, and you have the same bullet seated at 1.125, YES, the two cartridges would have different seating depths, which we measure from the case mouth to the bullet base.  BUT the size of combustion chamber is measured from the bullet base down to the internal bottom of the case, so the combustion chambers will be the same size, even if the seating depths are different, given the exact same bullet at the exact same OAL.  If that doesn't make sense, think of the bottom of the case as being at more or less the same location as your shell plate on your press while you're loading.  With two matching bullets loaded to the same OAL, the distance from those bullets' bases to the shellplate are the same regardless of how tall the cases are.

So just use .75 for your case length all the time.  It's an easier number to deal with, and you want to have a standardized case length so you're comparing apples to apples while looking at seating depth.

Also, keep in mind that creating data points at this level is extra credit work.  I do it.  I encourage others to do it.  There are uses for it, and there's a lot to be said for having a broad, comprehensive understanding of everything that's going on.  But understand that it's extra.  People have loaded their own ammo for a long long time without paying attention to that sort of thing, so if you're having a conversation some day with someone you found out loads his/her own ammo, as well, and you start talking about some load you recently developed and the decisions you made regarding the differences between your seating depth of .225 and the published data's depth of .190, don't be surprised if that person looks at you like you have a lobster on your head.  The extra credit work is good for you, but not everyone wants the extra credit work.  I know a guy who doesn't even set up his seating dies to a load a particular bullet to a particular OAL.  He eyeballs it.  "Hmmmmmm.... ohhhhhh... about right there looks good."   Seriously.  Still has all his fingers and everything.   

[IDescribe]

I know that is a lot of questions, but I thought I had a good handle on determining proper OAL based on reading the stickies and many previous threads in this forum.   Now you have me second-guessing myself, and I need to make sure I understand properly before proceeding any further.

I'm pretty sure Wobbly was talking about you lengthening from 1.090 to 1.110, not shortening to 1.110.

Your understanding is just fine.

Given a particular bullet and a particular pistol, there will be some OAL, below which you will start having feeding issues.  With CZ pistols, it seems to be down near 1.000 where you are almost certainly going to have problems with most bullets, but on a case by case basis, any bullet might start having problems at lengths longer than that, and there's no good way to predict it, so you have to find out the hard way.  As a general rule, you shouldn't go shorter than you need to in order to account for plunking and accuracy tuning.  Wobbly was just suggesting that 1.090 was almost certainly shorter than necessary, so there was no reason to load that short and tempt the failure-to-feed demon into showing up.  He wasn't saying you were likely to have feeding problems.  He was just saying there was no reason to find out.

The couple feeding issues I've had with 9mm Luger and CZ have turned out to be related to Filthy Pistol Syndrome.  And I've had a couple different bullets I load down to 1.060.  No feeding issues for me related to OAL yet.
 

[painter]

I think Mr.W is suggesting a length that he had experience with, and knows the results. Your thinking is otherwise correct. Don't over think it too much.

[baldrage]

I THINK Wobbly is saying he'd be inclined to use 1.100 or 1.110 instead of Hodgdon's OAL of 1.090.  I don't believe he's suggesting you shorten the OAL of 1.125 that you have been using down to 1.100 or 1.110.  You're at a seating depth of .224 already at the 1.125 you have been using.

Ahh, OK, thanks.  My initial understanding was correct, then.  Glad to hear I was not way off-base.

Yes, your points on internal combustion/pressure chamber make sense to me -- very intuitive.  If bullets are same size, seating one bullet deeper than the other would cause more pressure.  Check.  I understand needing to be careful if using a longer bullet than was used in load data so you do not inadvertently shrink the size of the combustion chamber and cause more pressure.  In my case, my bullet is longer then was used in Hodgdon load data, but I am not seating it as deeply, so should not be an issue.

Painter -- thanks for your feedback as well.  I know that much of the info provided by the tribal elders on this forum is"graduate level" info -- way above and beyond what most reloaders worry about.  I will try not to over-think things!

[baldrage]

OK, I loaded up my first batch of ammo using 124 gr RN FMJ bullets from Rocky Mountain Reloading, Winchester SPP, HP-38, and Blazer Brass cases.  Target OAL of 1.125 and 0.378 taper crimp.  I made five rounds each at 4.4 gr, 4.5 gr, 4.6 gr and 4.7 gr.  I made all 20 rounds one a time, using my SDB as a turret press, and visually verified that each case received a powder charge during the loading process. 

Actual OAL results ranged from 1.120 ? 1.129, and taper crimp results ranged from 0.3770 - 0.3785.  All 20 rounds passed the plunk test in my barrel ? ?TINGed? when dropped in, rotated freely, and dropped out under their own weight when turned upside down.  All of the primers appear to have seated properly ? look similar to seating depth on factory Blazer ammo, and I cannot feel any anomalies when running my finger over them.  Are there any other inspections or measurements I should do prior to test-firing these rounds?

EDIT to add:  as I was loading up these 20 rounds, I pulled apart a couple of the rounds using a kinetic bullet puller, and I did not see any rings or markings on the bullet from over-crimping.

[Boris_LA]

Are there any other inspections or measurements I should do prior to test-firing these rounds?

As a part of visual inspection check for case cracks. Sometimes brass cracks while seating the bullet from stretching. Otherwise it should be good for a first test.

[Wobbly]

I know that is a lot of questions, but I thought I had a good handle on determining proper OAL based on reading the stickies and many previous threads in this forum. Now you have me second-guessing myself, and I need to make sure I understand properly before proceeding any further.

Sincere apologies, sir. (Write that down as another internet first for the CZ Fourm... an on-line apology!) I mis-read your post and thought you were going to use the 1.090 length you were discussing. My bad!

However, there is no "correct" or "proper" cartridge OAL. It's anything between 1.000" as a suggested Min OAL and whatever the "push test" determines is your Max OAL. So you get to make the choice, and 1.125" is as good as anything else. Maybe better, since you can use that with about any 124gr RN out there.

You have such a wide OAL range to work with by going with 1.125" that your priorities now change to achieving good "feeding" and adequate "bullet insertion depth". 1.125" covers all those bases. Good choice.


I'll try to have my glasses on next time. 

(Note to self... Breakfast cereals should be eaten with milk, not porters and stouts.)

[Wobbly]

I THINK Wobbly is saying...

I think Mr.W is suggesting...

I think Mr. W should have his eyes checked, and not try to answer posts before his coffee takes full effect. Thanks guys for the brilliant mind reading.

 

[baldrage]

Sincere apologies, sir. (Write that down as another internet first for the CZ Fourm... an on-line apology!) I mis-read your post and thought you were going to use the 1.090 length you were discussing. My bad!

However, there is no "correct" or "proper" cartridge OAL. It's anything between 1.000" as a suggested Min OAL and whatever the "push test" determines is your Max OAL. So you get to make the choice, and 1.125" is as good as anything else. Maybe better, since you can use that with about any 124gr RN out there.

You have such a wide OAL range to work with by going with 1.125" that your priorities now change to achieving good "feeding" and adequate "bullet insertion depth". 1.125" covers all those bases. Good choice.

No worries!  Glad to hear it was just a miscommunication, and not a fundamental misunderstanding of the basics on my part!!

[copemech]

OK, I loaded up my first batch of ammo using 124 gr RN FMJ bullets from Rocky Mountain Reloading, Winchester SPP, HP-38, and Blazer Brass cases.  Target OAL of 1.125 and 0.378 taper crimp.  I made five rounds each at 4.4 gr, 4.5 gr, 4.6 gr and 4.7 gr.  I made all 20 rounds one a time, using my SDB as a turret press, and visually verified that each case received a powder charge during the loading process. 

Actual OAL results ranged from 1.120 ? 1.129, and taper crimp results ranged from 0.3770 - 0.3785.  All 20 rounds passed the plunk test in my barrel ? ?TINGed? when dropped in, rotated freely, and dropped out under their own weight when turned upside down.  All of the primers appear to have seated properly ? look similar to seating depth on factory Blazer ammo, and I cannot feel any anomalies when running my finger over them.  Are there any other inspections or measurements I should do prior to test-firing these rounds?

EDIT to add:  as I was loading up these 20 rounds, I pulled apart a couple of the rounds using a kinetic bullet puller, and I did not see any rings or markings on the bullet from over-crimping.

Are you going to chrono this stuff? These sound pretty HOT to me?

[IDescribe]

Are you going to chrono this stuff? These sound pretty HOT to me?

They're inside the standard pressure load data, .1gr shy of max.  They're shallowly seated FMJ, a little deeper than most other 124gr FMJ, but not much.  I suspect he'll hit a PF of 133 at 4.5/4.6.  This a common 9mm minor load.  They're not going to be particularly hot.

[1SOW]

I'll pick 4.5 grs  at 130PF.  (Given jacketted or plated  .355 bullets)

Who's next to estimate the results?   ----- = ... PF

[copemech]

I guess I am missing something here as I should be at about 130PF with the HP-38 loads at 4.1 gr with the PD124 the last I tested. Granted I am stuffing them in a bit deeper at around .255  I think with the 1.075 COL, but I would not think that would make a .4 gr difference.

I was at 4.0 gr  1021 fps

4.2 gr  1069 fps

I do still need to run the 4.1 over the chrono, but for now they just work and nothing special here.

[IDescribe]

Copemech, you're talking about a PD 124gr JHP.  You are estimating at an OAL of 1.075 with 4.1gr of HP-38 that you would be around 1045, which is a reasonable assumption based on those straddling data points.

With a PD 124gr JHP at 1.085 and 4.1gr HP-38, I got 1033.  So your estimate seated .10 deeper than mine in a CZ you'd estimate to get about 12 feet/sec more than I did, which suggests our data agrees pretty well. 

But he's shooting an FMJ-RN.  Different animal.  I have one string shot with HP-38 and the Precision Delta 124gr RN (sized .356 instead of .355), but the data doesn't look right, and I think it was at the just slightly too low, poor pressure seal point where a .2gr increase will jump it up 60-70 feet/sec.  I think my guess is good.  We will see.   

Either way, in terms of "hot" or not, he's inside the Hodgdon standard pressure data.  He's fine.

[baldrage]

Are you going to chrono this stuff? These sound pretty HOT to me?

They're inside the standard pressure load data, .1gr shy of max.  They're shallowly seated FMJ, a little deeper than most other 124gr FMJ, but not much.  I suspect he'll hit a PF of 133 at 4.5/4.6.  This a common 9mm minor load.  They're not going to be particularly hot.

Yes, what IDescribe said!  I don't have a chrono, and I'm shooting at an indoor range where I wouldn't be able to set one up, anyway.  Hodgdon load data was 1.090 OAL for 125 gr FMJ, min load of 4.4 gr H-38, max load of 4.8 gr.  I'm using 124 gr RN FMJ, OAL of 1.125, and loading from 4.4 - 4.7. So, a little longer OAL than Hodgdon's data, and stopping .1 gr short of their max load.   

Assuming I get out of work at a decent hour today, hoping to make it to the range tonight to test-fire my first reloads!