On the block that pushes the shell into the barrel ( The brown one ), I just added a slope so after firing, the shell has something to slide off of. Then I extended the green block above the shell a little bit to the left so that the rounds wouldn't get stuck, and the gun worked fine.
The Linkage is right, I didn't write the variables properly when I originally made this scene. I haven't bothered to update it so that it will work when loaded through saves.
You can fix the issue simply by doing the following:
Select the 8 springs that are in the escapement mechanism and set the spring constant to 56450, and the damping to -0.0110029 ( make sure it's negative).
Make sure the density of the ring part of the escapement is set to 50kg/m2.
