Having the blues on recently built AR. Problem is this was supposed to be my flagship AR. Problem: I am getting a random issue of failure to lock back after last round. Compounded by it being totally random and unable to duplicate intentionally. About every 3-5 magazines I get this failure. No other cycling issues. Other symptoms of note: -Ejection is about 1:30-2:30 with brass bouncing off deflector. Indicating over gassed. -Ejection is weak, hitting the ground about 3 feet away, indicating under gassed. - Ejection pattern and strength does not change when swapping buffer weights, buffer springs, bolts or carriers. Suppressed and not show no difference. -Recoil is normal, not notably sharper or weaker than a standard middy. All parts are new. Build Specs: -Barrel: 16" mid-length Noveske N4 light barrel with pinned gas block. Research shows Noveske runs a little over gassed, but nothing more than H2 is usually needed. -BCG: Ranier Arms nitride. Gas rings and key all good to go. Black insert and O ring on extractor. -Buffer set up: Geisselle Braided 42, with both H1 and H2 weights. -Bolt Release: Strike Industries. Moves freely and engages when manually cycled on empty mags. No BAD lever or anything hanging off it. What I have tried so far, doing so one at a time. -Different ammo. All ammo has been brass cased mil-spec or better that has always been solid performers in other ARs. -Different mags. All quality mags that have been good in other rifles. AR mags are cheap, I toss any that don't function. -Buffer weights. With the super 42, I tried H1&H2. Then tried Spikes ST-T2 which on my scale is between H1&H2, with a standard buffer spring. Have not tried standard carbine buffer yet. -BCG was swapped with a BCM, and another Ranier Arms. Things I've checked. -Gas block has no notable leaks. -Gas tube is straight and center. No unusual wear on gas key make up. Pinned into gas block properly. -No unusual wear on BCG, gas key is properly staked. So...what the heck am I missing here? Thanks in advanced.