About every other shot, the slide fails to return completely to battery, requiring hammer to be re-cocked before it will fire. Dirty or clean, makes no difference, and there's no space age lubricant I haven't tried on the floating chamber, including some of the "dry" ones. Ammo makes no difference either, except that it functioned more reliably with Stingers, but which are too expensive for plinking. Is it possible a stronger recoil spring would help...or maybe a weaker one? Unit made in the '80s, mounted on a Gold Cup frame.