I tested it and 38S&W works just fine in Comp III speed loaders. I think if you bubberized them and shortened the center trigger post they would be freakishly fast. The Comp I speed loaders I bough for my J-frame work well with 38S&W in my Iver Johnson Safety Automatic. I would love to have a Webley in 38/200! And yes 38S&W is larger than 38 Special or 357Mag, at least if we are talking about caliber...