This is basically a process of grinding from the reinforcement substance that was added to strengthen the buffer tube/extension region, and reprofiling the area to make it resemble the first A1 spot. This could contain some welding or filling of some type. Use the pictures down below for example: The https://remingtonijihd.onzeblog.com/31223056/helping-the-others-realize-the-advantages-of-colt-m16a1-for-sale