Captain33036
Member
Hello
I have a new 9mm AR: Bushmaster lower and CMMG 9mm upper, 9mm buffer. The magwell block appears to be the cheap ProMag plastic one.
I get failures to feed about every 1 in 10 rounds (loading 10 in a mag). Not sure if it is a break in issue, mag related or magwell block related.
It came with a very cheap plastic ProMag magazine and in the first trip to the range, I had quite a number of failures. Mostly failure to feed. Even when cycling by hand.
The feed ramp also looked as though it was flat and banged with a hammer a couple of times. Weird.
SO: I took a stone to the feed ramp and rounded it out a bit. Since the failures seemed to be mag related, I ordered new Metalform ones (20 round).
I used those today...very tight...heck of a time getting rounds in (I will get a loader). This got better after some lube and working the mag. Whew.
Reliability was much improved, from the start, using these new mags. I loaded just 10 rounds at a time (thumbs hurt) and got one failure to feed in every mag. Same results, both mags.
I was wondering if anyone had any advice or input on this issue? I have only had a chance to get 200 rounds through the gun.
Will this go away as the gun breaks in?
Will this go away when the mags break in a bit more?
Should I stone the feed ramp more?
Should I consider replacing the magwell block? (this can be expensive...so I would rather avoid, if I can...but....the gun MUST run 100%...regardless of cost).
Any advice would be welcome.
Thanks
John
I have a new 9mm AR: Bushmaster lower and CMMG 9mm upper, 9mm buffer. The magwell block appears to be the cheap ProMag plastic one.
I get failures to feed about every 1 in 10 rounds (loading 10 in a mag). Not sure if it is a break in issue, mag related or magwell block related.
It came with a very cheap plastic ProMag magazine and in the first trip to the range, I had quite a number of failures. Mostly failure to feed. Even when cycling by hand.
The feed ramp also looked as though it was flat and banged with a hammer a couple of times. Weird.
SO: I took a stone to the feed ramp and rounded it out a bit. Since the failures seemed to be mag related, I ordered new Metalform ones (20 round).
I used those today...very tight...heck of a time getting rounds in (I will get a loader). This got better after some lube and working the mag. Whew.
Reliability was much improved, from the start, using these new mags. I loaded just 10 rounds at a time (thumbs hurt) and got one failure to feed in every mag. Same results, both mags.
I was wondering if anyone had any advice or input on this issue? I have only had a chance to get 200 rounds through the gun.
Will this go away as the gun breaks in?
Will this go away when the mags break in a bit more?
Should I stone the feed ramp more?
Should I consider replacing the magwell block? (this can be expensive...so I would rather avoid, if I can...but....the gun MUST run 100%...regardless of cost).
Any advice would be welcome.
Thanks
John