Hello Ulverston (i used to live on Ulverston road here in Sheffield)
if your osprey is harsh on the firing cycle it could be that there's an air leak somewhere, i've had a few sidelever (and underlever) rifles that when shot, it feels like the piston is hammering into the end of the cylinder with very little buffering.
usually a new piston seal can cure it but sometimes it's wear in the loading tap which is much harder to deal with...
If you can get a smoother cycle the problem should go away...
John![]()