I believe that revolver was known (at the time it was built) as the Combat Masterpiece. In 1957, it became the Model 15. It was the 4” version of the Target Masterpiece, which was a 6”, target sighted, 38 S&W Special, K framed revolver.
A very nice revolver, I carried a Model 15 when I was in LE. Also used it in competition. They tend to be very good shooters.
Welcome from Iowa.
Your Combat Masterpiece was made in 1951. It became the M15 in 1957.
I have one in front of me that's a few years younger. It has the sweetest double action trigger pull of all my revolvers.
Get yourself some standard velocity ammo and shoot the heck out of it.