OAL question for Pistol ammo

[palealeyum]

Just starting to load .45 Auto and have a question regarding published OALS. I am testing 4 different powders and using Berrys plated and Precision polymer coated bullets.

Is OAL listed by powder mfgrs, bullet mfgrs or my Lyman manual based on feeding or is it based on the amount of the bullet seated? I would imagine that bullet seating depth is related to the pressure created.

Published values for the .45 Auto in my lyman manual vary from 1.161" to 1.272" and the SAAMI shows a 1.190 min and 1.275 max.

So, should I be focusing on OAL within these ranges based on feeding and not worry about varying the OAL from published loads?

Thanks in advance.

[J-cat]

It is based on bullet fit in the chamber. Different bullet profiles need a different OAL. Some guns have very short and tight freebore and require a shorter OAL still. You should make some dummy rounds to test.

[twotacocombo]

It's a balance of pressure and clearances. Too long, and the bullet may not fit in the magazine or will get jammed into the rifling when you chamber it. Too short and pressures can spike to dangerous levels. OAL is dependent on bullet shape as well as weight. Heavier bullets tend to be longer, which means you have less room to play with in either direction. If you're at all concerned about pressure, I'd suggest loading to the longest published OAL for that bullet weight and profile. As long as it doesn't jam into the lands when chambering, you're good to go.

[mark501w]

Set the dummy round to your mag . See if the cartridge will extract. Check for marks from lands . Save dummy round, develop load from there.

[nahpungnome]

I would also suggest manually cycling a couple of dummy rounds. Make like 3. I was playing with FP 225gr .45 and it passed the plunk test in my CZ 97, but every single round after the first would FTRB. They would not manually cycle either. I ended up having to shorten the OAL down to 1.18 from my original 1.20. They FTRB a lot less, but there were still some failures at the range today.

[Fishslayer]

Depends on the bullet. RN will usually have a longer OAL than HP or SWC.

The general OAL for 230gr RN is usually 1.25" - 1.26" ish. Exceptions might be a lead bullet with a "step" at the bearing surface.

You will want to "plunk test" in a case gauge. I use the one that comes with every pistol I own... AKA the barrel. The finished round should "plunk" when dropped into the chamber and fall free when you tip the muzzle end up.

Note the use of "usually" and "generally." There are exceptions to every rule but I load Berrys, X-Treme, HSM and Bear Creek 230gr RN bullets all at 1.25" and they function fine. FWIW I use the barrel from my RIA for testing. I've found that if it "plunks" in that chamber it will plunk in everything else.

[Rwnielsen]

Load up a few dummy rounds, stack them in a mag and see if they'll rack through your pistol without hanging up.

[sbmunshi]

You can also use the barrel. Remove the barrel and put the round in. It should be flush.