On Target Products (OTP) Autococker Parts, manufactured by B & M and Brahim Estephen. Well know OTP parts include the G1 Bolt, barrel kits, IVGs and many other parts. Jörn Joghans wrote me an email about the G1 Bolt... "I noticed that you wondered what the spring-loaded back [on the G1 bolt] was for. This was a solution to enable the use of a mis-timed Cocker. If you shortened the trigger pull enough, you would start blowing air up the feed tube, because the bolt started retracting too early in the firing cycle. This bolt produced a longer dwell in the chamber by being able to extend itself, and once the back block stopped in its rear position, the spring in the bolt pulled it back together, allowing a new paintball to chamber. That was the idea anyhow."