Really the face of the bolt was dirty, the chamber had some laquer on it, and the dirtiest parts were the piston, and about an inch of the op rod. Unfortunately when I took the dirty picture on those 2 parts I didnt use the better lit up area of my garage, like the clean photo.
The 9mm handgun had about 100 rds through it, and it was almost as dirty, the gas piston rifle had 200 rds of brown bear through it. Ive compared PMC to brown bear and the PMC produces more carbon.
The bolt carrier was still wet, with a bit of crud at the top that ran down from the chamber (from the oil after firing it, I wet the moving parts down pretty good, but not where it drips).
Compare these parts to a DI rifle with the same amount of lube (done once) and 200 rds fired through it. There was a guy standing there with his S&W M&P15, after we fired a few mags I handed him my bolt carrier, he was shocked how cold, clean, and wet it was.
The recoil difference is definitely noticeable with this GP rifle over a DI model, my wife comments about her shoulder getting beat up when she shoots it. I notice it, but Im used to the difference. Also the rifle is a bit louder than DI, not so noticeable now as it was the first several times we shot it.
When fired side by side with that S&W it sounds overall a bit different, hard to explain it, sounds good. Its more fun to fire rapid over the DI model, again hard to explain, you would have to feel it to see what I mean, maybe the design of bolt carrier, and the action of the piston assembly (also that Sprinco spring made a noticeable difference when i installed it).
