P90 Nicking Brass

[greener]

I generally shoot lead semiwadcutters in my P90. I've started getting a nicked brass in the loading cycle about one/magazine. The nick in the front of the brass casing is serious enough that the round won't load. I've checked the pistol and cannot find any sharp surface. I've disassembled and cleaned the mags, no problems there. I don't think it happens with FMJ, but I shoot very, very few of those.

Any ideas on what's nicking the brass?

 

[gb6491]

Where is the nick located in relation to the barrel? Top? bottom?
If the nick is at the top, they may be catching on the lower edge of the barrel hood.
At the bottom, the maybe catching at the bottom of the ramp or where the barrel throat transitions to the chamber.
Did this just start happening?
Does it happen if feeding by hand?
Are you shooting reloads? - Have you checked the round's OAL? Changed how you crimp?
Have you tried different magazines? How old are your magazine springs? What condition are the magazine feed lips in?
Regards,
Greg

 

[greener]

Thanks for the response.

Rounds: 200 gr LSWC handloads. OAL 1.244", diameter at case: .454" Crimped with a Lee Factory crimp die. Rounds are randomly checked for barrel fit and a number of rounds are cycled through the mag into the pistol and out during reloading.

Top or bottom: Not sure. the round jams and requires force on extraction.

Timing: Past several months. I keep looking and can't see a problem.

Doesn't happen with FMJ
Mag springs are originals. same mags. mag lips are smooth. This is a P90DC circa 1998 by serial number. I've had it for 3 years but I doubt it has seen a large number of rounds. More since I've had it. Boring at 15 yards. :lol:

Possibly sharp edges around the feed ramp

Pistol still looks pretty good

 

[gb6491]

As it has been a recent development, I think new magazine springs would be a good place to start.
Regards,
Greg

 

[Donaldjr1969]

As it has been a recent development, I think new magazine springs would be a good place to start.
Regards,
Greg

I second that. based on the OP's latest reply, he is not the original owner. Therefore he has no idea how the pistol was cared for despite appearances. Was the magazine stored fully loaded without being used or manually unloaded for an extended period of time? And if the spring has weakened, it may be a bit too slow to fully push up a LSWC round far enough to smoothly slide across the feed ramp. As we all know, a slightly weak spring will work fine when the slide is manually cycled yet under live fire, the slide will move too fast for a weak spring.

If the springs are ok, could it be possible that the crimp may not be 100% tight on a LSWC and it could be slightly unseating not unlike how LRN bullets may unseat firing a 357 rapidly in a lightweight revolver such as the LCR357 or a S&W Airweight? Just a thought...

 

[greener]

Possible the springs could be it. Will look at spring replacement or a new mag (~$35, ouch).

Fired about 35 rounds today alternating mags. Had one round nick. Still don't know if top or bottom, but they look like this

I crimp the heck out of these rounds. Both the P90 and my Taurus PT1911 have relatively tight chambers. What will load in a Kimber, may not load in either of these.

 

[Donaldjr1969]

I am going to just take a wild guess and say it could be hitting the feed ramp. Others probably will be able to give you a better guess due to the fact they have far more experience with a P90 than I do.

If I may make a suggestion, after loading each round into the magazine, take a magic marker and make a line across the top of the round at the 12:00 position before loading the next round. You would repeat that until the magazine is full. Then after you inspect a nicked round, you can get a better idea where it could be hitting.

 

[greener]

Good idea w/marker.

 

[Fishslayer]

When I bought my KP90 new I got 4 bad mags from 2 different sources. Ruger "repaired" the mags (didn't specify) and my "issues" went away. Of course, I wasn't nicking brass that I know of. The rounds would have to feed and eject for that to happen.:twisted:

Mag springs are pretty cheap at Midway. I rebuilt 2 mags with 7 rd springs & followers. YIKES! Hope ya kept the mag loader...

Have you tried other LSWC besides your own?