This Is basically a strategy of grinding from the reinforcement material which was included to fortify the buffer tube/extension space, and reprofiling the area to make it resemble the original A1 space. This might involve some welding or filling of some type. Use the pictures below for example: Up for https://reidjljie.sasugawiki.com/6694101/the_5_second_trick_for_colt_combat_elite_commander_45_acp