they won't cycle a auto[/color]( even with a can, I've never had them cycle a auto) but they are slient from a gun with a good can.
you hear the action moving and the impact of the bullet.
They seem to function just fine in my Mark II's and 10/22's.

I really like these rounds, especially for critter control when you don't want to wake the neighbors.
I have noticed that since the case is so short and so much bullet is exposed, that after you shoot a bunch of them and then go back to regular rounds, the regular rounds can be tight going into the chamber.