Fit perfectly in Pietta 1860 army. Just lightly stoned various contact points a it fit perfectly. The cylinder locks up perfect with no slop and stop is completely engaged into cylinder slots. Had to replace original it had a bur that broke off then when half cooked bolt stop would fall off hammer cam and the cylinder would always be locked up. Strange for a gun that never was shot it broke while cycling after its first tear down and pre 1st shooting cleaning. It is to short and the burr must have just been making everything work. But alls well for $15 now it works like a charm.