08-25-2013, 06:23 PM
The main concern is that the Barrel Extension is one of the most critical parts to containing pressure when the charge is ignited. As such, it is a strong steel that is heat-treated, with a surface hardness, and inner ductility.
The main areas on the barrel extension that bear stress are the threads where it is attached to the barrel, along the circumference of the part, and the inside teeth and substrate steel where the lugs of the bolt bear against it.
The question is, does polishing and lightly de-edging of the feed ramp side of the extension compromise the part's strength. I haven't seen anything to indicate that it does, but I would caution to remove as little as material as possible. I don't use any grinding tools, but just a soft polish wheel that is conical in shape, with a round nose. It has fine abrasive material embedded in a rubbery tool head.
I basically spend a lot of time placing the barrel back in the upper, comparing, then removing it and polishing some more.
The main areas on the barrel extension that bear stress are the threads where it is attached to the barrel, along the circumference of the part, and the inside teeth and substrate steel where the lugs of the bolt bear against it.
The question is, does polishing and lightly de-edging of the feed ramp side of the extension compromise the part's strength. I haven't seen anything to indicate that it does, but I would caution to remove as little as material as possible. I don't use any grinding tools, but just a soft polish wheel that is conical in shape, with a round nose. It has fine abrasive material embedded in a rubbery tool head.
I basically spend a lot of time placing the barrel back in the upper, comparing, then removing it and polishing some more.