Dear forum members,
one of my two M4 Shotguns is showing significant abrasions on the barrel where the pistons are moving. (see pictures below). Furthermore piston protruding about 7mm out of the tube as compared to to other one.
Both guns have a round count of about 400, mostly slugs.
Production date is 2003, 14" version, 2 barrel port holes.
Both guns differ in the design in that area, is somebody aware of a major technical change during the years?
Thank you for your help,
regards
- hkgermany