Damaged case mouths on 45 ACP

[Shooter64738]

I'm having a problem with some 45 acp loads I've been working on. This load had been working well with a 200 grain round nose but Ive ran out of those and switched to a 230 grain round nose.

The last round in my magazine ends up with a big dent in the edge of the case mouth. I marked the back of the cases, so I could tell for certain which side was getting damaged, and it appears to be the ejection port side of the case. Keep in mind it's only the last round shot in the magazine, and the slide always locks. I'm sure it's not under pressure stove pipes. Those are pretty easy to spot. It appears to be too much pressure,slide speed to fast, pressure dropping to fast, something like that. It does it with all 3 magazines, and even does it with no magazine. The remedy for it was to pull the bullet out to an OAL of 1.26, instead of the book spec of 1.23. It does function now, but I would like to know if my assumptions are correct. Does anyone have any thoughts?

I've shooting these in a springfield 45 xd service model. I used universal clays in these loads with the 230 grain bullet. I've shoot several differnet loads out of it, they always take some tuning, but this one was by far the hardest.

 

[rcmodel]

Are you talking about a case mouth dent in the empty case?

If so, it is caused by the empty case doing a 180 off the extractor hook and slamming into the slide on the way out.

The ejection pattern is different while there are still rounds in the mag due to them pushing up on the empty case as it comes out of the chamber.
The last round has nothing under it to push it up at a differnt angle.

If you are talking about a dent from feeding, then yes, the OAL with differnt bullet shapes or length determine the break-over angle into the chamber as the round comes out of the feed lips. In general, longer always works better.

rc

 

[Shooter64738]

The problem is on the extracted case, after firing. I changed to oal to give the powder a little more volume, and hopefully lower the pressure enough to make it stop. Seems to have worked, and I've not had the problem again. Ive had a few people give me some theories on what was causing it, but none of them made much sense. I used a video camera, and you can see it's hitting the ejection port sidewall. The only question I have left is whats causing it. My theory is excessive slide speed, but I thought I would pass it around to some people who might have another idea.

 

[Steve C]

You don't say what your load is but if you had one worked up for a 200gr bullet and then simply substituted a 230gr bullet you've likely gone from a ighter load to a much heavier load.

I think your analysis of the slide speed being the culprit is correct. Simply reducing the load a bit or changing the recoil spring to one that's a bit heavier would probably cure the problem. The other cure would be to have the ejection port relieved as is done with most target 1911's and currently many factory production pistols.

 

[hpluseleven]

FWIW, I experienced the same thing (or something similar). I'm new to pistol cartridge reloading and I just shot my first .45ACP reloads yesterday. (I think) I noticed the same problem you're seeing - I picked up my empties and several of them had damaged case mouths. I asked a guy who works at the range where I shoot who has been reloading for a long time, he thought it was an ejector problem.

I was shooting:
5.7gr Unique
Speer 230gr TMJ RN
Fed LP primers
in my Taurus PT145

I'm pretty sure it happened more often than just the last case in the mag for me. Not every case, but quite a few.

 

[rcmodel]

Dented case mouths on .45 ACP shot out of unmodified 1911's have been around since, uhhhhhh, 1911.

It is no big deal.

Small dents iron out during sizing & expanding.

More severe dents where the mouth is folded in too much to enter the sizing die are fixed before sizing with a tapered punch or the points of a pair of needle-nose pliers.

It's really no more then a nuisance and doesn't hurt the case.

rc

 

[soloban]

Not a big deal

I bought 500 empty .45acp cases off of Gunbroker and about half of them have that characteristic dent in the case mouth. Once it goes through the depriming/resizing die it irons out the dent.

 

[Noveldoc]

If you pistol has been around for a while, recoil spring may be getting tired. Call Wolffs and get a new one, maybe 2 lb above factory if you shoot heavy loads.

Also a slip on plastic recoil buffer only costs a few bucks and saves a lot of wear and tear.

Tom