Another thing I learned was I prefer shooting my M57 rather than my M58. I am not a big fan of the frame and stocks on the M58.
While the frames are different "types", they only differ at the top. The grips are interchangeable.
There was a local dept. that issued the M58 years ago and the ammo they chose was the factory JSP. Many of the officers replaced the as issued PC style grip with targets to ease the felt recoil during requalification.