Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3949053.

One Version with Big block up and one with the small block up, because some barrels have them upside down. This is a Mod for the Alpha Trooper, it replaces the orange mini barrel in the front. There is a little groove to insert a rubber O-Ring into. So even barrels without endstop fit and sit snuggly. Prints good without supports.