Air Arms Owners Club

My AA s200 lifting the bolt every time I fire it’s very off putting,
As a “O” ring blown somewhere it’s only just started to do this, I’m not feeling any blow back air on my cheek so a bit stumped on this one help please.
Ps the bolt is after sales quite heavy but been ok for a number of years no problems at all with it till now.

check the spring and ball ,it locks the cocking lever , undo the grub screw on top of the action block, give it a clean and make sure the spring is not broken. if ok then check the near side of the action where the probe for the actuates the lever for the magazine system. it wears the corner off the block and keeps jumping undone.