Beretta 390 Jamming Problem

Bud1 · May 15, 2000, 03:50 PM

I have a Beretta A390ST with about 30,000 rounds through it. The modifications to it are a lengthened forcing cone, porting, and the trigger pull and creep adjusted by a gunsmith. I thoroughly disassemble and clean the gun every 700 - 800 rounds or so, and am well versed in how and where to lubricate.

Besides breaking the occasional connecting rod (2 in the 4 years that I have had the gun), I have not had any problems. Last weekend, I started getting a jam about every 3rd or 4th shot. The hangup would occur as the bolt was trying to close with a live round, sometimes on loading, and sometimes after the first shot. The shell would stick about 1/2 way into the chamber, and I would have to forcibly pull back on the bolt carrier handle to get it loose and let it slam home. It sometimes took a couple of tries before the bolt would close completely on the live round.

I use only factory ammunition, and the hang ups occurred evenly between the Federal Gold Medal and Winchester AAs that I use. The shells were fresh, and had no swelling or defects that I could see. I tried some of the same shells in a duplicate gun, and had no problem.

I completely disassembled the gun, and could not find any obvious problems. I re-scrubbed the chamber, and then swapped out parts from a duplicate gun 1 piece at a time to try and isolate the problem. The recoil spring in the stock appeared OK, but I did not disassemble it. Instead, I went ahead and started out by replacing the entire receiver assembly (sans the bolt and trigger assemblies). Nothing seemed to make any difference until I replaced the entire bolt assembly, and now it seems to work OK when I function test it. I could not find any obvious defects in the old bolt, but am wondering if shotguns require headspace adjustments. I will be back out to try shooting it this weekend, but am still stumped as to what could have caused this.

Any ideas?

Thanks,

Bud

George Stringer · May 15, 2000, 10:26 PM

Bud, shotguns do sometimes get the headspace out of whack but your gun isn't showing a symptom of that. It sounds more like something to do with the carrier/bolt relationship. Have you contacted Beretta? George

Bud1 · May 16, 2000, 08:01 AM

I'll see how it runs this weekend, and if I have further problems, I will give Beretta a call. Good suggestion; thanks.

May 15, 2000, 03:50 PM	#1
Bud1 Senior Member Join Date: February 4, 2000 Posts: 194	I have a Beretta A390ST with about 30,000 rounds through it. The modifications to it are a lengthened forcing cone, porting, and the trigger pull and creep adjusted by a gunsmith. I thoroughly disassemble and clean the gun every 700 - 800 rounds or so, and am well versed in how and where to lubricate. Besides breaking the occasional connecting rod (2 in the 4 years that I have had the gun), I have not had any problems. Last weekend, I started getting a jam about every 3rd or 4th shot. The hangup would occur as the bolt was trying to close with a live round, sometimes on loading, and sometimes after the first shot. The shell would stick about 1/2 way into the chamber, and I would have to forcibly pull back on the bolt carrier handle to get it loose and let it slam home. It sometimes took a couple of tries before the bolt would close completely on the live round. I use only factory ammunition, and the hang ups occurred evenly between the Federal Gold Medal and Winchester AAs that I use. The shells were fresh, and had no swelling or defects that I could see. I tried some of the same shells in a duplicate gun, and had no problem. I completely disassembled the gun, and could not find any obvious problems. I re-scrubbed the chamber, and then swapped out parts from a duplicate gun 1 piece at a time to try and isolate the problem. The recoil spring in the stock appeared OK, but I did not disassemble it. Instead, I went ahead and started out by replacing the entire receiver assembly (sans the bolt and trigger assemblies). Nothing seemed to make any difference until I replaced the entire bolt assembly, and now it seems to work OK when I function test it. I could not find any obvious defects in the old bolt, but am wondering if shotguns require headspace adjustments. I will be back out to try shooting it this weekend, but am still stumped as to what could have caused this. Any ideas? Thanks, Bud

May 15, 2000, 10:26 PM	#2
George Stringer Staff Alumnus Join Date: October 12, 1998 Location: Earlington KY Posts: 2,299	Bud, shotguns do sometimes get the headspace out of whack but your gun isn't showing a symptom of that. It sounds more like something to do with the carrier/bolt relationship. Have you contacted Beretta? George

May 16, 2000, 08:01 AM	#3
Bud1 Senior Member Join Date: February 4, 2000 Posts: 194	I'll see how it runs this weekend, and if I have further problems, I will give Beretta a call. Good suggestion; thanks.