That's a good deal on a 2.5" M19! You can run 125gr .357 loads through the gun, just don't put 1000s of rounds of that type of ammo through it or it may loosen up a bit.
I've got a 2.5" M66, same as your gun but stainless steel, and I feed it mostly mid-range .357 loads (158gr, 173gr Keith bullets over Unique) along with 38spl wadcutters for practice.
So long as you don't run an 8lb keg of H110 under 125gr JHP's through your gun every year, you'll be fine.
