The Smith and Wesson MG is not rated for plus p.It sortais in the middle between SAA and Ruger pressures. It will wear with pluspand you won't be happy. But Grizzly Cartridge makes a 260 Wide Flat Nose for the 45colt that is a standard pressure loading. So does Buffalo Bore. I haven't used the Buffalo Bore but the Grizzly shot great out of my MG.