What Chris said. 148 practice 38s (target wadcutter) may be reasonably close to a 158 357 combat load, but in general run the same weight.
In terms of a defense load, a big healthy 6" barrel gun like that will perform REALLY well with Gold Dot 158 357s. Speer, Georgia Arms, Proload, Black Hills all load the same projectile at around the same fairly mellow speed, 1,250fps from a 4", a bit more in your 6".
If those are too hot to handle, scale back to any good 38+P; there's been a number of recent threads on this subject. Short form (all these are 38+P):
Winchester or Remington 158+P lead hollowpoints are good stuff;
Winchester's 130grain Supreme +P works;
Gold Dot 125+P as loaded by Speer, Georgia Arms, Proload, Black Hills is about on par with the Winnie 130;
Speer's new 135 Gold Dot +P is the replacement for the GD 125 and seems to be even better; only Speer has it in loaded ammo so far and it's *scarce* as heck;
Remington Golden Saber 125 +P - not sure I like these out of a 2" but a 6" will fling 'em out plenty fast enough.
Hornady XTP 125 +P - consider this a specialty load of sorts - it has a delayed expansion (brass jacket vs. copper) and doesn't go as "fat" as some of the others, but punches VERY deep. Good for cold-weather situations but only from a 4" or (pref.) 6" barrel; doesn't do well out of a 2". The whole XTP line is really a hunting load, not a defensive JHP series, but works in some limited circumstances.
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At present, those are the only loads I'd recommend in 38+P.
Bufallo Bore will soon be shipping wild-hot variants of the 158 lead hollowpoint +P (similar slug as Win/Remmie above but over 150fps faster, 1,000fps from a 2" barrel!) and a super-hot loading of the Gold Dot 125+P. When they ship, both will be VERY worthy of consideration, esp. that 158 - it beats ALL other 38+Ps for raw power, it's the blown nitrous-injected 500inch drag motor of the 38Spl world.
Cor-bon is shipping a new "uber-38", their 100grain Pow'R'Ball. While the idea of a round that "cannot possibly clog on clothes" is great, I'm concerned as to how light it is and want to see independent test data on it before I'd ever use such a thing. That said, the 45ACP 165grain Pow'R'Ball was a respectable performer in short-barreled 45s so...I ain't necessarily knocking it, I just want some data.