New reloader - question on COAL

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Cylentnyte

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Hey everyone, new to reloading here and these forums have popped up countless times in my search for various info on the topic, so figured I'd say hi :)

I'm loading 9mm luger and just finished up my first test batch with a middle-ground load straight out of the Lyman handbook: 4.1gr of W231, Berry's 124gr HBRN TP, and 1.150" COAL. I'd like to try out some of their others like the Flat Point or Target Hollow Point variants but their bullet lengths are different. Do I get COAL data directly from the bullet mfr.? Berry's has COAL listed for their bullets right on the page for each one so I didn't know if that's determined by the people who make the bullet, or the people who come up with the load data.

I was thinking I just take the difference in bullet lengths and subtract that from the original COAL I was working with, so ie. going from the .612" I have now to the .534" flat points, making a new COAL of 1.072" (which is close to the 1.060" Berry's has on their site anyways). Did I understand this right?
 
Welcome to THR and the incredibly fun world of reloading!

In my experience you should use COL data from the loading manuals as a guide.....as a documentation of what the publisher tested. It is not a prescription for what you should use.

The most important thing to determine is what COL is needed for the specific bullet you're using in your specific gun. The COL documented in the manual may not work in your gun.

So use "the plunk test" to determine what your bullet/gun need. In a nutshell: Build up a dummy round and drop it into the pistol's chamber (after removing the barrel from the gun). When you turn the barrel upside down the round should fall freely out into your hand. If it doesn't....seat the bullet a little deeper.

Generally I've found I can start at the starting load from the manual, but I've had an instance or two where my COL was a LOT shorter than what was in the manual, so I started at a starting charge less than the starting load in my manual(s).

I've had an instance or two where I've looked at bullet length and done some math to figure out how much space there was in the case based on how deep I was seating the bullet, but these were esoteric situations. To load the scenarios you're describing above this type of thing isn't necessary. Focus on figuring out what COL each bullet needs in your gun, then look for as similar as data as you can in load data.

You'll hear the following a lot and it should be followed: Start low and work up. Don't assume a middle-range charge in a load manual is middle-range in your situation. I just did a new load this week and what was considered "lite" in the data was mid-range....approaching hot....in my gun.

Hopefully this makes sense. And again - welcome!

OR
 
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Welcome to THR.

Cylentnyte said:
9mm luger ... W231 ... Berry's 124gr HBRN TP, and 1.150" COAL

Do I get COAL data directly from the bullet mfr.?
Click to expand...
When referencing published load data, you will often find different OALs and this is due to different test barrels used for pressure testing done to develop published load data. For pressure testing, often a test fixture is used (a universal receiver that accepts different caliber barrels) that is single shot/bolt action which does not feed from a magazine.

So for us reloaders with semi-auto pistols that feed from magazines, we not only have to determine the OAL that will work with the barrel (Called Max OAL as posted by otisrush), we also have to determine the OAL that will reliably feed and chamber from the magazines (Called the Working OAL, which can be same length as Max OAL but often shorter).

While OAL of 1.150"-1.160" with 124 gr FMJ/RN bullets can work, if you are looking for greater accuracy, since case wall gets thicker further down from case mouth, many reloaders test shorter OALs and often end up using shorter 1.135" due to greater accuracy produced. This is particularly applicable when using lighter powder charges as shorter OAL will produce greater neck tension that will increase chamber pressures for more consistent/efficient powder burn.

We recently addressed determining OAL for Berry's 124 gr HBRN-TP bullet with W231 powder work up in this thread - https://www.thehighroad.org/index.p...arding-load-development.869175/#post-11518003

These are steps from the thread for load development and powder work up:
  • Determine the max OAL that will freely fall into the barrel and spin without touching the rifling (To minimize gas leakage)
  • Then determine the max working OAL that will reliably feed/chamber from the magazine by incrementally decreasing the OAL (Say by .005")
  • Conduct full powder work up to identify the powder charge that produces smallest groups (Reducing start/max charges by .2-.3 gr if using shorter OAL than published)
  • Incrementally decrease the OAL to see if group size decreases (Neck tension overshadowing gas leakage)
 
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For 9mm I load as long as my chamber and throat will allow. 9mm is very sensitive to changes in bullet seating depth. For that reason I load as long as possible.
 
LiveLife nailed it.

1. Just like the power weight, the OAL in the load manual is part of the report the testers issued on chamber pressure. The OAL is not a recommendation it is part of the report.

2. Every gun maker cuts their chambers differently. The chamber for a Ruger is not like the chamber of a SIG, which is not like the chamber of the CZ.

3. Therefore, it is up to YOU, the reloader, to determine what works in your chamber.

4. And that OAL number will change with every new brand and shape of bullet. The converse of which is also true... some of the bullets you buy may not work in your barrel !!

Let the fun begin !
 
rfwobbly said:
it is up to YOU, the reloader, to determine what works in your chamber.
Click to expand...
From Barrel vs Bullet Max/Working OAL thread - https://www.thehighroad.org/index.p...col-for-reference.848462/page-2#post-11465109
  • Berry's 124 gr HBRN-TP: 1.155" - 1.145" - Taurus PT-809
  • Berry's 124 gr HBRN-TP: 1.169" - Glock 22, KKM 40-9 conversion barrel, factory G17 magazine
  • Berry's 124 gr HBRN-TP: 1.169" - Glock 22, Tactical Kinetics 40-9 conversion barrel, factory G17 magazine
  • Berry's 124 gr HBRN-TP: 1.169" - Glock 23, Lone Wolf 40-9 conversion barrel, factory G17 magazine
  • Berry's 124 gr HBRN-TP: 1.169" - M&P Shield 9mm, factory barrel, factory magazine
 
All very good posts here.

If you decide to load long COAL, besides the plunk test, don't forget to test the fit in the magazine! Don't ask me how I know. :eek:
Texas10mm said:
For 9mm I load as long as my chamber and throat will allow. 9mm is very sensitive to changes in bullet seating depth. For that reason I load as long as possible.
Click to expand...
 
This is all really helpful info and exactly what I was looking for, thanks everyone. I’ll definitely be doing some exploratory work on a CZ 75BD to see what its limits are at some point. For now I’ll work off published load data until I’m more experienced with the process.

LiveLife I’m sure I’ll be coming back to that thread more than once, thanks for that. The powder work up makes sense with the reduction in COL. I did a plunk test with one of the 1.150” test rounds and it spun freely as well as loaded into the mag just fine, so I’ll see how this tests at the range.
 
Happy to say the first runs were a success, getting 2-3” groups at 15 yards but I think that’s me more than the ammo. Haven’t practiced in months...kick definitely felt less than the range’s 115gr Federals
 
Cylentnyte said:
getting 2-3” groups at 15 yards
Click to expand...
That's pretty good.

I consider following to be my accuracy standards for "decent" ammo:
  • 1" at 7 yards
  • 2" at 10-15 yards
  • 3" at 25 yards
During powder work up, loads that produce closer to 1" at 10-15 yards are deemed accurate and those that produce closer to 2" at 25 yards to be very accurate.
 
LiveLife said:
That's pretty good.

I consider following to be my accuracy standards for "decent" ammo:
  • 1" at 7 yards
  • 2" at 10-15 yards
  • 3" at 25 yards
During powder work up, loads that produce closer to 1" at 10-15 yards are deemed accurate and those that produce closer to 2" at 25 yards to be very accurate.
Click to expand...

You must have some really accurate pistols. Most pistols won't shoot to those accuracy standards.
 
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