I picked up both a 22lr and 22 mag from BCA to try out.
My range session with the 22lr upper was very short lived – 19 rounds total before I put it back in the truck so no one would get hurt. It death jammed on round 2 (case stuck between CH and bolt, requires using a tool to pull the bolt back to free the shell) and then catastrophically ruptured a case on round 7 and a second case on round 19. There were several partial ruptures between that were not immediately noticeable.
The pin did consistently light off the primers, but I do also have an full power trigger group (Palmetto enhanced) in the lower I was using:
Unfortunately, the upper was rupturing casings, sending some pretty large brass fragments flying out of the ejection port, one of which ended up in my knee and was dug out with a knife. Notice the swelling on all the non-ruptured or partially ruptured cases:
Marked the place the brass was embedded for monitoring:
The issue is a partially unsupported chamber at the extractor groove:
I did notice the extractor cut when the upper arrived and thought momentarily “that looks like a case rupturing machine” but figured it must be part of the design to have the case partially supported by the extractor. I'm still unsure whether all the 22lr chambers are cut like mine by design or whether this is a QC issue and I just got unlucky. The upper did have powder residue inside of the upper when it arrived that had been partially cleaned away, but not on the bolt, almost like it was a return that had the bolt replaced and then re-sold. I can say that this BCA does seem to handle ruptured cases rather poorly compared to the CMMG bolts. Those contain the powder and gas fairly well (I have a 17hm2 upper built on a CMMG bolt that does rupture the occasional case) sending a bit of gas back through the charging handle, but this one spews most of it right out the port, and with the rupture happening on the right side of the case (the CMMG bolt tends to rupture on the bottom edge in my experience), the brass shards end up flying out rather than being contained by the upper/lower/mag. I’ll probably print out a rail mounted gas deflector to keep the gas and brass from coming back towards the shooter before I try the 22mag, I think – that one has a lot more gas than a 22lr in case of a rupture.
Although there seems to be a fully supported chamber on the 22mag, I lost my nerve to shoot anything else from BCA yesterday, so I just packed it up and called it a day after 30 min on the range.
CHECK YOUR CHAMBERS AND BRASS! Post up a photo so we can see if this is just my rifle or if all of them are unsupported. Even if you have not had a rupture, if there is any swelling it is cause for concern. Ambient was 95F, and in my experience (with the 17hm2 upper mostly) ruptures are highly temperature dependent -- the HM2 will rupture at pretty consistently at 110F but run like a sewing machine at 60F. I probably could have shot the BCA with only swelling had it been 50 degrees cooler.
Looking at the reviews on BCA's product page, this does seem to be a widespread problem, so I can't help but suspect that the unsupported chamber is in the design. I just can't see these barrels passing even a quick visual QC check (even at BCA...) if the chamber is supposed to be fully supported. I have heard of a gen 1 and gen 2 of these BCA uppers, but I am not sure which I have. I ordered these uppers in mid-April.
I hope I got a lemon and the rest of you guys have fully supported chambers and no ruptures. I'm also hopeful BCA will resolve this quickly and I'll have another neat little upper for the collection. I REALLY wanted to love both of these uppers...
My range session with the 22lr upper was very short lived – 19 rounds total before I put it back in the truck so no one would get hurt. It death jammed on round 2 (case stuck between CH and bolt, requires using a tool to pull the bolt back to free the shell) and then catastrophically ruptured a case on round 7 and a second case on round 19. There were several partial ruptures between that were not immediately noticeable.
The pin did consistently light off the primers, but I do also have an full power trigger group (Palmetto enhanced) in the lower I was using:
Unfortunately, the upper was rupturing casings, sending some pretty large brass fragments flying out of the ejection port, one of which ended up in my knee and was dug out with a knife. Notice the swelling on all the non-ruptured or partially ruptured cases:
Marked the place the brass was embedded for monitoring:
The issue is a partially unsupported chamber at the extractor groove:
I did notice the extractor cut when the upper arrived and thought momentarily “that looks like a case rupturing machine” but figured it must be part of the design to have the case partially supported by the extractor. I'm still unsure whether all the 22lr chambers are cut like mine by design or whether this is a QC issue and I just got unlucky. The upper did have powder residue inside of the upper when it arrived that had been partially cleaned away, but not on the bolt, almost like it was a return that had the bolt replaced and then re-sold. I can say that this BCA does seem to handle ruptured cases rather poorly compared to the CMMG bolts. Those contain the powder and gas fairly well (I have a 17hm2 upper built on a CMMG bolt that does rupture the occasional case) sending a bit of gas back through the charging handle, but this one spews most of it right out the port, and with the rupture happening on the right side of the case (the CMMG bolt tends to rupture on the bottom edge in my experience), the brass shards end up flying out rather than being contained by the upper/lower/mag. I’ll probably print out a rail mounted gas deflector to keep the gas and brass from coming back towards the shooter before I try the 22mag, I think – that one has a lot more gas than a 22lr in case of a rupture.
Although there seems to be a fully supported chamber on the 22mag, I lost my nerve to shoot anything else from BCA yesterday, so I just packed it up and called it a day after 30 min on the range.
CHECK YOUR CHAMBERS AND BRASS! Post up a photo so we can see if this is just my rifle or if all of them are unsupported. Even if you have not had a rupture, if there is any swelling it is cause for concern. Ambient was 95F, and in my experience (with the 17hm2 upper mostly) ruptures are highly temperature dependent -- the HM2 will rupture at pretty consistently at 110F but run like a sewing machine at 60F. I probably could have shot the BCA with only swelling had it been 50 degrees cooler.
Looking at the reviews on BCA's product page, this does seem to be a widespread problem, so I can't help but suspect that the unsupported chamber is in the design. I just can't see these barrels passing even a quick visual QC check (even at BCA...) if the chamber is supposed to be fully supported. I have heard of a gen 1 and gen 2 of these BCA uppers, but I am not sure which I have. I ordered these uppers in mid-April.
I hope I got a lemon and the rest of you guys have fully supported chambers and no ruptures. I'm also hopeful BCA will resolve this quickly and I'll have another neat little upper for the collection. I REALLY wanted to love both of these uppers...
