The CZ-52 has the H&K Roller Block breech. This allows this pistol to shoot the Communist Bloc 7.62X25 Sub-Gun Ammo. It is a fun gun for handloader experiments.. These pistols are .308 and can push 98 grs. bullets to 1,900 fps. With lighter bullets the CZ-52 can hit 2,000 fps. It is in the class of the .357 Sig. with the proper hand loads. The uncomfortable grip clip can be covered with the rubber grip adapters. It is an "Ugly Duckling" but is accurate and flat shooting at 100 yards. New firing pens and roller block lugs are easy to purchase. Do not dry fire the CZ-52 which has the orginal firing pins. They can and will snap. The CZ-52 military arms are marked "rid" on the left side of the frame. Civilian and copies are not "rid" stamped. These guns sold for $89 dollars for sometime. The prices are now edging on $400 bucks for a nice one.