What caused this bulge?

View · by **Ron Burgundy** on Sat May 09, 2015 8:46 pm

Picked up a handful of 9mm (mixed head stamp) after a USPSA match today. I tumbled and started to sort tonight and found a bunch like the one in the picture. The picture is the worst one. I've seen Glock bulge but this wrapped the whole way around in a uniform pattern. Other head stamps had less bulge but the primers were really

View · by **crbutler** on Sat May 09, 2015 10:07 pm

Major 9mm plus a oversized chamber base (opened up to make feeding reliable.) most likely.

Can also be caused by the gun opening up too early, but most guns used in USPSA are locked breech.

Generally not an issue as long as you are using only 1X fired brass- it stretches like that.

Problems arise when it gets used again.

Toss that brass.

View · by **Seismic Sam** on Sun May 10, 2015 4:24 am

And it might not hurt to doink that stuff with a hammer so it doesn't make it back into your case flow. The 1x rule for 9mm major is one you do NOT want to violate!!!

View · by **Ron Burgundy** on Sun May 10, 2015 6:23 am

Enlarged chamber makes sense. I guess I'll be spending a little more time sorting. And culling...

View · by **Seismic Sam** on Tue May 12, 2015 7:51 am

Ron Burgundy wrote:Picked up a handful of 9mm (mixed head stamp) after a USPSA match today. I tumbled and started to sort tonight and found a bunch like the one in the picture. The picture is the worst one. I've seen Glock bulge but this wrapped the whole way around in a uniform pattern. Other head stamps had less bulge but the primers were really

The case was pregnant and about to have a litter of .22 Shorts when it was fired....

View · by **usnret** on Tue May 12, 2015 3:32 pm

What caused the bulge........pressure.

View · by **SIGP240** on Wed May 13, 2015 9:15 pm

I see that on my Underwood 10mm fired brass. Their quality control allows some weak brass through and it will balloon