I'm sorta confused too about the "small" frames. I have seen some Ruger Flat tops in 45 Colt say they have the .357 frame. Are these not safe for hot rodding? I have some pet 45 loads that push .454 Casull specs
There is a difference between the Flat Tops and the Blackhawk series. The Flat Tops are built on the meduim
frame. At one time Rugers used the designations of "R-", "MR-" and "MR-44" to denoted frame size. The R size was the Single Six, the MR was the .357 Blackhawk, and the MR-44 was the .44 Magnum, these all three-screw era designations.
The medium frame is safe for heavy loads, though ill-advised. For the .454 neighborhood loadings, stay with the biggest frame.