In the S&W ammo brochure that came with new guns up until about 1978 they claimed 1500 fps for these rounds, which was very misleading. That was using "industry standard test equipment", which for the .357 was an 11 inch unvented barrel. In 1979 they published a new brochure, this one using real S&W revolvers to produce their test results, after the industry standards changed. Now they claimed 1068 fps from a four inch barrel Model 66, 1146 from a 6 inch barrel Model 66, and 1152 from a 8 3/8 inch Model 27. In my opinion, it was this change from long unvented test barrels to real world handguns that mistakenly made many people think the ammo of yesteryear was more powerful.
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