Brian I have a polished spring with a stainless ball in the front going into the cup on the back of the hammer.
As I have said the new style is able to rotate, I proved this with a marker pen and several cocking cycles.
I think the very front of my hammer is slightly of centre . So when it rotates around it occasionally drags on the inside of the action.
My logic is this could have a couple of effects, slowing the impact on the valve or slowing the valve closing .
I'm thinking the second effect may help to cause my high shots that I have been witnessing .
I think the first approach will be to reduce the end diameter then put a floating guide around it.
I'm also thinking Spring guides for the backend, but may do in stages to see if each has an effect.
I forgot to point out that on stripping it has highlighted a marked area on the end of the hammer.