The 2.5" .357 revolver gives up very little in power. Remember, highest velocity really isn't important, in fact it can be a real problem! The *right* velocity for the bulletyou are using is what counts, not the fastest velocity.
Typically, you can expect a 35-50 fps change in velocity for each 1" of barrel change. Most .357 rounds are factory chronyed from 4" barrels.
I have chronyed the Winchester 145 gr. Silvertip (my defense load of choice) from 4", 3", and 2.5" barrels. This load is factory rated at 1290 from a 4" vented barrel. I have clocked it at 1307 from a 3" GP-100 barrel and 1241 from a 2.5" Model 19.
Trust me on this: the 145 gr. Silvertip moving at 1241 fps from a 2.5" .357 barrel is an extremely competent round in terms of modifying the behavior of an attacker. Being a little heavier than the 125 gr. bullet, it will tend to penetrate arms, coats, lots of FAT and muscle, etc. a little better... getting down deep to the vitals.
In winter time, this can be a real plus in cold climates. In fact, I prefer the 158 gr. Gold Dot in cold weather, because this round can be relied upon to provide even better penetration. If you get some 225 lb. ******* wearing a heavy leather coat, several layers of winter clothing, layers of fat gut, and muscle beneath that... you don't want to be shooting fast, lightweight hollowpoint ammo... those are more likely to flatten out too quickly on the heavy coat and clothing and not penetrate deeply enough to get through it all and reach the deep vitals.
Penetration MUST happen, beyond that, expansion is a nice frosting on the cake, if you can get it without giving up deep penetration. You never know when one of your bullets might have to penetrate an arm or two, leather, heavy clothes, layers of fat and muscle! I'm just not at all comfortable relying on lightweight hollow point bullets at high speed. Give me heavy bullets at moderate speeds for deep penetration.
It's a known fact that in general, heavier, slower bullets penetrate deeper (and can more readily push through arms, bone, layers of heavy clothing, fat, and muscle) than light, fast hollowpoints, which have a greater likelihood of overexpanding and underpenetrating, especially when pushed very fast! In addition, the fast, light bullet loads cause more flame cutting and forcing cone erosion on your dear gun. Therefore I limit my .357 shooting to target loads and, for defense, to 145 gr. Silvertips and 158 gr. Gold Dots.
Have no fear that your 2.5" .357 won't generate enough power... this great caliber is powerful enough to be VERY effective, even in snub-nose .357's.
As far treating your revolver well is concerned, note that .357 caliber 110 gr. and 125 gr. loads cause more flame cutting and forcing cone erosion than .357 loads with heavier bullets. All the more reason for choosing the heavier bullet weights in the .357 caliber.