I've done some research over the last few days and all I'm doing is regretting buying my CMMG lower...but in any case I have it, it's the only brand my local rifle store sells and I live in the great state of NY so buying stuff is already a hassell. In any case I bought and built my CMMG lower about a year and a half ago with a CMMG LPK and Geisele SSA trigger and slapped on a Magpul stock and grip...all without a hitch and it wasn't until now that I'm looking to buy a complete upper just to finish my build and scratch the 308 itch that I'm reading more about possible incompatibility issues between uppers and lowers (should've done more research in the beginning). In any case I'm looking at an Aero Precision M5E1 20" complete upper and was wondering if I need to worry about it fitting or being that off that I can't even get it to work? Reason for choosing the upper is price is right (obviously) and they offer a 20" barrel and it's all complete and (so what I thought) headache free ready to pop on and be done. Question just lies if I will run into any problems with this choice upper or should I just settle and spend a bit more and get a CMMG complete MK3 upper with a shorter barrel?
