So here are the specs on my AR pistol. Aero Percision lower with High Standard LPK. Magpul K2 pistol grip. Spikes 7" buffer tube with carbine spring and T2 heavy buffer. RRA MPI BCG. Spikes Tactical Charging handle. RRA upper with RRA 7" barrel. GG&G quad rail and A frame front sight . RRA stand alone rear sight. Thing fired like a champ today using AE 55 and 62 grain fmj as well as polymer tip AE 50 grain varmit round, 6" groups at 25 yards first time out with it. Not bad if I say so myself. Now when funds are replenished an aimpoint pro will be next on the list and maybe swap the AFG2 from my carbine AR on to the pistol and get a proper verticle grip for the carbine. No issues, no failures and no burns. Bolt carrier locked back like a champ with the Spikes T2, which was just a random guess on what to use.