45 ACP Bullet Seating Determination

R

RougeLeader

Inactive
Hello everyone! I've been working on some 45 ACP loads and ran into some failure to fire issues. It was an issue with the bullet seating depth, just a few thousandths off.

My question is if there is a better way to determine the proper seating depth for an arbitrary bullet for semiautomatic cartridges to prevent primer detonation failures than trial and error and educated guessing. Yes I do know that the 'proper' depth for this may conflict with cartridge feeding with some gun/projectile combinations. I'm just worried about the primer strikes in this case.

Just to take care of some other sort-of-on-topic replies, I do trim and prep my brass, I do know what seating depth is, I do know seating depth will be different for various projectiles, and I do currently have a working safe loading.
-RougeLeader
 
What weight bullet? What configuration[shape]? OAL? And, do you have dial calipers?
We have some unknowns here.
 
Rifletom,
My current loading is a 200gn LSWC. OAL is 1.260-1.261'' as tested between 20 rounds. I do have dial calipers, digital calipers, and a large micrometer.
 
Seat the primers untill they bottom out in the primer pocket....no primers sitting high, that's bad.
Use your guns barrel and do the plunk test...when it passes the plunk test make sure it will fit into the magazine.
Make up some dummy rounds and you can see if they manually cycle from magazine into chamber and eject. If they do ...it's powder, primer and range time.
It isn't rocket science ...don't over think it.
Gary
Do a search on the term "plunk test" you will see. Basically you use your guns barrel as the chamber gauge . Chamber gauge's don't ensure a round will fit your guns chamber....so just use the barrel . When the round drops in (plunk)and drops out (plunk) that's doing the plunk test .
 
gwpercle,
I do exactly as you said. I do make cycle-test dummy rounds, a least 2 mags worth actually for each load variation, and do seat my primers properly.
If by the plunk test you mean literally dropping them into the disassembled chamber and seeing if they are flush with the barrel hood then yes I do this as well. These are just standard SOP.
 
I don't understand what bullet seating depth could have anything to do with failure to fire if the round chambers.
A round that's too long will fail to chamber, this is why the plunk test. A high primer will fail to fire.
 
I do trim and prep my brass
Click to expand...

First off, I'm nothing close to a "serious" reloader, but I am lazy and proud of it.

One reason I load 45 ACP is because there's no need (according to my past research) to trim the brass. The 45 ACP headspaces on the case mouth, and those cases do not stretch as they can on other calibers. So I next to never check case length on them, unless something gets fishy.

If I were you, I'd give consideration to the possibility that your trimmed brass causes the cartridge to seat a tad low, and that would also carry the primer along with it, and that might be the cause of your failures to fire...light strikes due to increased distance from the firing pin to the primer.
 
I have found that bullet design severely impacts bullet depth in regards to both failure to fire and failure to feed for my pistol. If I seat to 1.26'' with this bullet design then I get feed failures and severe leading. This leads to the conclusion that the OD of the LSWC is impacting and deforming against the end of the chamber. If I seat to 1.23'' then I get severe failure to fire issues, figure 1:12 rounds would be a failure.
I have tested this with remington and CCI primers, over 1000 rounds of ammunition between variations, and a constant powder load of bullseye.
Is it possible that my 1911 is just picky? Have you guys seen this sort of behavior?
 
Rifletom,
I honestly hadn't considered the reduced length of trimmed brass and being and issue. I'll load non-trimmed once-fired for a few hundred loads and see what happens. You make a good point. A simple solution that for some stupid reason I didn't even think of.
 
I have not seen bullet seating to affect primer ignition.
Do they fire if you cock the hammer and hit them again?
If so, that is a sign of a high primer. The first hitvseats it the rest of the way and the second fires it.

Does your gun have a titanium firing pin? Those can contribute to misfires.
 
Jim,
I actually do have a titanium firing pin. I just had it installed as my previous pin had failed... come to think of it within a week or two of the time that these issues were encountered.
I was not aware that it would change the functionality of the weapon.
 
RougeLeader, the credit goes to Carmady regarding case length. You'll get this figured out, as it isn't difficult once you get rolling.
 
Seating depth of the bullet has nothing to do with your failure to fire. That's a completely different issue.
 
The plunk test is used with you barrel , with the barrel removed drop a loaded round in your chamber the bullet shouldn't extend past the barrel hood and will not stick in the chamber . You never have to trim 45acp cases . I use to until the people on this forum proved to me the cases never get to that length to trim . You can try the plunk test with just a case but it's for a loaded round test .
 
If the round will chamber than OAL wil not effect primer ignition. If the round will not chamber the round will not fire I suppose...

What are the exact problems you are getting? Failure to go into battery, trigger problems, failure of the firing pin to ignite the primer? We need more detail otherwise everyone is just guessing.
 
reddog81
Correct on OAL , if the round won't chamber you slide wouldn't close . I use the Lyman chamber gage to test each round . Just another tool on the shelf.
 
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failure to fire issues
Click to expand...
Do you mean the round does not fire when the hammer falls?

When you drop the hammer on a wooden pencil with eraser, what happens?



I do trim and prep my brass, ....
Click to expand...

Really? To what length? Fired or sized?
 
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