On mine, I have the inserts, I have the extra cylinder, the jamming up rarely happens, the problem is the barrel coning. There seems to be three level's of M-53's , mint hardly shot with no coning, shot and coned, and those that have machined back barrels for removing coning. Barrel on mine is coned, have a 8 3/8 N.O.S. barrel to be fitted on, but then won't shoot it . Have another spare barrel that's been cut way back many times would need ejector shortened to use it. Plan for now is to enjoy shooting the coned gun as long as it doesn't hurt the front of the Jet cylinder????? Even knowing these problems would still buy this gun and glad to have mine. At the range booths get a kick out of the expressions when they think it's just another K- frame then see the Jet Rounds being loaded!