Open Source Disc Shooter

This is a redesign of my prior attempt at building an open source disc shooter.

I'm not sure which kind of disc would be best. So, I've designed 9 different kinds. There are three with 2 holes, three with 3 holes, and three with 4 holes (plus a center hole for each). There are three with those holes beveled up to the right, three not beveled at all, and three beveled up to the left.

The barrel is in two halves, which should hopefully fit together. There's a firing pin as well, with n