Cleaned the AR10 I showed pics of earlier. Just powder residue (Smoke's red). First patch with Ed's without acetone, then tight clean patch - hardly dark. Soaked patch for the upper, came out BLACK with residue. 168gr GC slick sided > 2500 fps I figure. Alloy seems like it's good, just pushed too fast. 40Sw had a little toward the muzzle (smoke's gloss black), chore boy fixed, much softer alloy. AR10 (both rifle and carbine uppers) are original DPMS before Bushy or Rem took over. They just shoot! Only original problem was metal mags that needed the lips adjusted to feed properly.