I hate all the new Knight breech plugs. I would drill and tap and put removable vent liner in. All the Lehigh plugs are 17-4 stainless steel I believe. Knight said that was to expensive and went with a cheaper steel. Though it's still better then T/C and CVA I like what we originally designed the best. So to make the current Knight plugs better you gotta put a removable vent liner in. If not, you'll wear the plugs out fast due to design.