![]() The bulged loads you are showing must be using a very FAST burning powder - which is OK in a locked breach pistol, but not a blow-back rifle or AR pistol. with 3.2 grains of Vihta Vouri N-310 powder. My competition pistol load was a Zero brand JHP 1.150" C.O.A.L. Its not so much the rifle as it is the load. Out of my LOCKED BREACH pistols, the 147 grn JHPs clocked 875 FPS and did not show pressure signs on the primer or brass.īUT - out of the Uzi, they bulged the cases similar to your photos. OP: I have seen the EXACT same thing happen with my Glock/CZ pistol competition load when used in a carbine - in my case it was a friend's open-bolt Uzi registered SMG. I chronied all these rounds and they were all right where I thought they be (900-1000 fps) so Im not thinking this was a pressure issue?īTW- same rounds shot through Glock 34- no bulging. Second picture is the same subsonic loads (147g bullet, 960 fps) with the suspect brass (top) and other random brass (below) Shooting LIGHT (subsonic) reloads- problems with SOME (problems seem to be with same brass as the chicom stuff) Shooting some Chicom surplus ammo Norinco green box)- crazy case bulges. It's hard to say specifically if you have just one problem or a combination of a few things that are causing the insane case bulging. Again, if the bolt is also not contacting the barrel face, that could be exacerbating the problem with "hot " ammo. Third, I'd look at the feed ramp cut around the chamber as it looks like it may be a bit more of a cut than necessary and may not be helping the situation. Second, I'd weigh the buffer to confirm weight regardless of markings. ![]() If the bullet lodges into the rifling when chambered, that can cause pressures to spike abnormally and would explain why one type of ammo works fine, but another looks overpressure. Have you shot the chicom loads or the reloads in any other firearms? If so, what were the results? Any signs of overpressure or insanely high velocities over the chrono? Have you checked your chamber to ensure it is cut fully and properly. If factory ammo is no problem, I would look at how hot the chicom stuff is and your reloads first. If the bolt face is not contacting the barrel face, that's an issue. here's a photo with a round chambered, and bolt closed (to evaluate if its seating)Ĭan't quite tell from that angle, but as long as the face of the bolt is contacting the barrel, you "should" be okay. Only about 20% of the rounds fired were bulged. They are all bulged at the same area you probably have a ring of a case in there. You said you were shooting reloads, bet you had a case separation.
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