The only problem is that the 2.5" barrels do not have full length case retraction. You will need to learn the extractor slap and shake. The -3 indicates which change of M19 that you have, it does not have anything to do with barrel length. You do have a nice revolver. Is it a round butt as it is 2.5"? K frames are being cut off in 357 Magnum from S&W. You got a good one, I would BEG for the M66 also!