Ok, I have an AR that I built from a stripped lower, and complete upper. The lower is from essential arms, and the upper (kit) i bought from ar-15kits.com Very easy to assemble, as the upper was all complete. All I had to do was install the LPK, and the stock, and then attach the upper and lower together. So, I have put about 80 rounds through it, and have had probably 5-8 no fires. The primer was hit, as you can see the "dimple" where the firing pin hit it, but no BOOM. (this is not a good failure. The M-16 Manual for the Army says if this happens clear the round within 10 secs, or else point the gun down range, and leave it for 15-20 mins before trying to eject, cause it might be a delayed BOOM) The ammo was cheap (Barnaul, nickel plated) and I am hoping this is the problem. Next chance I get, I am going to be shooting some federal. Anyone have advise on what might be the problem (ammo or other) Thanks!