
Originally Posted by
C4IGrant
I checked with BCM and all is normal and within spec. Once you tighten the barrel nut to at least 40lbs, the the spacing is virtually non-existent (at least with BCM barrel extensions). Also, if the barrel extension sits flush with the receiver ramps with no tightening of a barrel nut, there is a chance that you can get the barrel extension to be higher than the receiver ramps. This is the kiss of death and I have seen this from time to time on cheaper AR's.
So everything is good.
C4
Yeah, I've seen this with several quality uppers and I'd call it normal...both pre-assembled (Colt, DD, LMT, and BCM) and also uppers I've built.
As Grant said, the game ender is when you have a 'ledge' (a reverse of what is seen in the pix). That's when you either replace the upper, barrel , or both....or do some SERIOUS grinding on the feed ramps. Which is bad, because it is extremely difficult to maintain the same geometry (basically impossible by hand).
"That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892
"The body cannot go where the mind has not already been."
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