SpudFiles

I recently bought a Benjamin Maximus as a cheap PCP to mess around with, one of the things I'm looking at is the "slingshot" hammer valve as a method to increase efficiency.



One of the issues with hammer valves is that the hammer can bounce back after striking the valve stem, then return to hit the stem again, potentially opening it and releasing air after the projectile has left the barrel.

The idea here is that the hammer spring is on a guide that is stopped before the hammer strikes the valve, giving the hammer a measure of "free flight" towards the end of its trajectory and preventing it from coming back far enough to bounce.

Some further reading.

The co2 / pcp mine gun compresses the hammer spring when the bolt is moved to the side of the firing cannon, I mean when you close the bolt and not when you open it.
When you open the bolt, only the hammer moves to the side of the shooter, and it snaps into the trigger mechanism, but the spring does not compress. When you close the bolt, the spring is just compressed. I imagine that when firing, after hitting the firing valve, the spring is not loose, it maintains an important pressure on the valve stem, to avoid rebound, but insufficient to leave it open. I haven't noticed bounce from the hammer. The only "problem" is that it is quite hard to close the bolt, because the forces of compressing the spring and introducing the pellet into the firing barrel that is quite tight are added.