Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
11/7/2015 7:14:48 PM EDT
I just built my first upper. When I went to put in the new BCG, which is an R Guns NiB it was tight fitting. I pushed it in and it got stuck. Had a hell of a time getting it out without damaging anything. I have two other uppers besides the new one I built, one Spike's and another from AIM surplus, I believe it was built by them. The BCG from the Spike's and AIM uppers will go into the new upper without getting stuck. Also the R Guns BCG will go into the Spike's and AIM uppers without getting stuck....WTF? Any suggestions?
11/7/2015 8:33:56 PM EDT
[#1]
Can you clarify "pushed it in " ?
11/7/2015 9:10:07 PM EDT
[#2]
Quote History
Quoted:
Can you clarify "pushed it in " ?
View Quote

Just putting the BCG into the upper. Had to push it hard. Didn't just drop in.
11/7/2015 9:27:01 PM EDT
[#3]
Sounds like a case of tolerance stacking.
Try using the two older BCG's in the new upper and the new BCG in the older uppers for a few mags worth of ammo to see if it won't loosen things up a bit.
11/7/2015 10:58:00 PM EDT
[#4]
I just noticed the gas block is a little out of line in the clockwise direction when looking into the muzzle. Also noticed that the feed ramps are just a little off compared to the M4 cuts in the lower in the counter clockwise direction. Now i think either the nut is over torqued, the extension is out of spec, or the notch in the lower that engages the barrel lug is too big. Have to tear it down when I get time and check it out.
AR Sponsor