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JAG2955 wrote:Is the brass getting mangled by the chamber mouth, or by the ejection port sides?
I'm pretty sure it's getting mashed by the chamber mouth/breech face as the rifle tries to shove the empty back in at the same time it's trying to feed a fresh round.
Will it reliably lock the bolt back on an empty mag unsuppressed?
Yes, even with subs. It leaves the empty sitting on top of the mag.
That screams extractor/ejector to me.
It's a BCM BCG, so check under the extractor spring for a rubber o-ring and/or rubber insert. I think that BCM standardizes on them. They're not required, but they can help. Make certain that nothing is binding the extractor's movement. It's an easy disassembly.
Less easy is the ejector, it should be flush with the end of the bolt, closest to the barrel end. I have seen lots of these get stuck in the halfway or fully recessed on ranges in the military. I'm not sure what causes it. If it's not as hard as hell to push in, you might want to disassemble it, see if someone put the wrong spring or a broken/kinked spring in it.
Rifles can do weird things sometimes. I've seen an M16A4 WITHOUT AN EXTRACTOR fire ~10 rounds without a malfunction. I was wondering what the silver streak in the ejection port was. Then I realized it was the firing pin and the kid lost his extractor.
JAG2955 wrote:Is the brass getting mangled by the chamber mouth, or by the ejection port sides?
I'm pretty sure it's getting mashed by the chamber mouth/breech face as the rifle tries to shove the empty back in at the same time it's trying to feed a fresh round.
Will it reliably lock the bolt back on an empty mag unsuppressed?
Yes, even with subs. It leaves the empty sitting on top of the mag.
That screams extractor/ejector to me.
It's a BCM BCG, so check under the extractor spring for a rubber o-ring and/or rubber insert. I think that BCM standardizes on them. They're not required, but they can help. Make certain that nothing is binding the extractor's movement. It's an easy disassembly.
An o-ring came packaged separately with the BCG. I asked on another group what it was for, and was told that since I bought the BCM unit, which comes with a good spring, I should not need the o-ring, and that it could cause problems. Given that I have nothing to lose at this point, I will try the o-ring. I'd forgotten about it. It just seems like, if the extractor is the problem, it should be a problem with the can on too, but waduwino?
Less easy is the ejector, it should be flush with the end of the bolt, closest to the barrel end. I have seen lots of these get stuck in the halfway or fully recessed on ranges in the military. I'm not sure what causes it. If it's not as hard as hell to push in, you might want to disassemble it, see if someone put the wrong spring or a broken/kinked spring in it.
Ejector protrudes flush with the end of the bolt and is hard as hell to push in; I had to use the end of a pen. But I had to use the pen to get the extractor to move, too.
Cognosce teipsum et disce pati
"People come and go in our lives, especially the online ones. Some leave a fond memory, and some a bad taste." -Aesop
Cleaned the rifle and installed the extractor o-ring tonight. The action was pretty crudded up and I'm really learning to hate cleaning this thing compared to the AK. I don't think I am going to buy any more of the SIG ammo (or at least the subs), since I think that's where some of the worst of it came from.
I also noted that the set screw for the forward assist mechanism was backed way out. I put some blue loctite on it and tightened it. Last night when I took the handguard off to futz with the gas port, I noted that none of the screws holding it on were particularly tight, and a couple were actually loose. The set screws for the gas block were not really all that tight, either. I put some Rocksett on the gas block set screws, and will probably go back and loctite the handguard screws once it looks like I won't have to take it back off again.
One thing that was a bit of a pleasant surprise at the range, was when I let those other guys shoot it, I noted that it seemed a lot quieter standing even a few feet behind it, than when firing it myself. Wish I'd had my earpro off to get a better idea of the actual sound level, but there were some other guys shooting a few lanes down.
Cognosce teipsum et disce pati
"People come and go in our lives, especially the online ones. Some leave a fond memory, and some a bad taste." -Aesop
I still haven't gotten back to the range with this (the assholes in charge made ice cleats mandatory until further notice), but I did install an anti-rotation sling mount in the Hogue stock the other day:
I had to Dremel out the slot a little to make it fit, but it seems to be okay. This morning I removed my crummy sling that I made from plain webbing and some tri-glides, and installed a Vickers 2 point sling that I like so far.
Cognosce teipsum et disce pati
"People come and go in our lives, especially the online ones. Some leave a fond memory, and some a bad taste." -Aesop
Due to the school holiday I was able to finally make it to the range this morning and shoot the blackout again. The o-ring seems to have done the trick, and it functions fine unsuppressed now, with both supers and subs. Seems kind of cheesy, but I guess it's in keeping with the overall rube-job nature of the AR in general. Thanks to JAG for the advice that allowed me to get it working.
Cognosce teipsum et disce pati
"People come and go in our lives, especially the online ones. Some leave a fond memory, and some a bad taste." -Aesop
Netpackrat wrote:Due to the school holiday I was able to finally make it to the range this morning and shoot the blackout again. The o-ring seems to have done the trick, and it functions fine unsuppressed now, with both supers and subs. Seems kind of cheesy, but I guess it's in keeping with the overall rube-job nature of the AR in general. Thanks to JAG for the advice that allowed me to get it working.
