Just put the A3 flat top upper on my century built AR. Right up front, I do not care for the Russian ammo, but the polymer coated 62 grain stuff turned in 5 (3) shot groups under one inch center to center at 100 yards today. Not to clean burning, but accurate as heck. Beat any other stuff I had hands down. Other than cleaning, do you see any problems or possible damage to my SUR using this ammo?