Load 1 round into a mag and see if the bolt locks back, if it doesn't then gun is short stroking. I've heard that wolf can be underpowered, your rifle may be undergassed too. Hell, even heavy grease can do it.
Check the rings, make sure they're not lining up, check the gas key for leakage, make sure the rifle's oiled or just a THIN coat of grease. Oh yeah, check the gas tube for restriction/blockage.
Absolute last resort is to open up the gas port.