About 1966,I wrote to S&W asking if I could safely fire .38-44 (.38 Hi-Velocity) ammo in an M&P/Model 10.

Sales Manager Fred Miller replied that it was safe, but if I did that much, the gun would loosen sooner and that recoil would be uncomfortable. He strongly advised getting a .38-44 or a .357 Magnum if I expected to shoot .38-44 ammo extensively.

Gun writer Jan Stevenson said that Colt's metallurgy was superior to that of S&W, and I think he was right. But I still wouldn't fire a lot of that hot ammo through a Police Positive Special or Detective Special. I wouldn't fire it at all in a Cobra or Agent, unless there was an emergency and only that ammo was on hand.