[HKFan9]

So I have built a bunch of AR's using various stripped lowers from different roll marks and different manufactures with no problems what so ever.

My buddy wanted me to build him up a rifle so we shopped parts, i told him pick a lower he wanted.. get it sent to my FFL, I will build the lower while you decide what you want to do with the upper.

He ordered a Aeropercision lower. I was always a firm believer in a lower is a lower is a lower... however I will admit I sub-consciously and consciously usually stick with the CMT receiver family. (Stag, Colt, Noveske ect.) Never any issues and CMT/Stag imho are a great company.

His lower came, I looked it over, everything seemed ok so I started assembly. Everything went great, except that I noticed the mag release was sticking pretty bad. It is semi-normal for people to complain of a sticky mag release when first assembling a lower, but the last one I built myself cured itself with in a minute. His however started to get worse.

I took it back off to discover there was grinding and chipping on the inside edge of the inside edge of the mag-well where the magazine catch slides back and worth. It seems that it is either that that edge was some what out of spec and catching on the mag release.... nothing a little file and stone wouldn't fix... or it seemed that it was out of spec and allowing the mag catch to shift or cant ever so slightly where it was grinding itself against the lower.

I think it is easily fixable (it also could be the parts from the DPMS parts kit he gave me may be out of spec).

Before I took action.. I was just wondering if anyone else had this issue or something similar... or any helpful suggestions.