The Kirst backing plate/loading gate is a slide-in fit, a quite snug, well fitting plate. The cylinder sets in front all held in line by the barrel and wedge. The purpose of attaching the backing plate with screws escapes me. It seems a solution for no problem. After all, cutting the loading channel removes a lot of the recoil shield. Drilling and tapping what metal is left doesn't seem too wise. IMHO.....
NRA, VCDL, USAF 1970-76 6200FMS CLARK FIELD,P.I.'71-'72- 18 SOS, NKP, THAILAND '72, BASE FLIGHT,KEESLER AFB,MISS '72-'74, CARSWELL AFB,TX '74-'76