Eliminate excess cylinder endshake on Colt and clones, plus all Ruger single action revolvers with these stainless steel gas ring shims. Installs between frame and the front of the gas ring to eliminate cylinder binding caused by the cylinder face rubbing the rear of the barrel, and helps cure headspace problems that can lead to misfires. Shim thickness of .0045" accommodates most revolvers that have cylinder endshake problems; remove material from the gas ring for "tighter" guns. Developed by master pistolsmith Ron Power as a cost-effective alternative to stretching the gas ring. Whether you're servicing a worn gun or building a custom one, these shims will help Mfg: Power Custom SPECS: Stainless steel. .0045" thick. For guns with base pin diameter no larger than .260" and gas ring no smaller than .380". Fits Gen. 1, 2, 3 Colt SA and clones, and all Ruger SA revolvers.