I recently purchased a Springfield Armory M1 Carbine. The magazine is a 15 shot Co2 but doesn’t have a follower to allow lock back on last shot. I found a link for a modified 3D printed one and asked if someone would be willing to print one for me. A helpful person did and produced a few for me at 15%, 50%, and 100%. The link suggested that 15% was enough. I stripped the mag and fitted one of the 15’s but it shattered straight away. Then I fitted the 100% and it’s still going well after many mag fulls. It also makes loading the BB’s easier without braking fingernails. Having the lock back is great and I don’t have to count shots now.
