Just gave this one a thorough inspection and deep cleaning. Plus, I was bored. No abnormal wear, but plenty of carbon fouling as always.
These rifles are “direct impingement” which means propellant gas is drawn off of a port in the barrel to unlock the rifle’s bolt and force it rearward. This expanding gas is sent from a gas block through a gas tube and into the bolt’s gas “key” which exerts force directly onto the bolt.
(just part of the semi-auto cycle)
Since gas is introduced directly into the bolt group, carbon and spent powder fouling builds up everywhere within the “upper” and “lower” halves of the rifle. These guns prefer to “run wet” (heavily oiled) and that enhances the build up level to over 9000. However, even with the dirtiest and cheapest ammo, the rifle will continue to run as long as it gets an occasional re-oiling.
All ready to get dirty again at the range.