Help fix an oldie

[Dauntless152]

I jave an old samurai semi auto marker. It only will work if the velocity adjustment as all the way in not really shooting very far at all
but it will re-cock normally. Once I raise the velocity the thing basically acts like it has no air and it’s sputters and it fails to re-cock. Hammer O-ring looks fine the sear is fine so I’m not sure why

[William the Third]

Are you 100% sure the striker/hammer o-ring is good and the correct size, and everything else appears "ok"? For some reason not enough air is being sent to the striker/hammer for recocking. This is why with the velocity screw all of the way in it works, because more air is being forced back to the striker/hammer.