Arizona, there is no reason to shoot +P loads in that nice old gun.I don't think it'd blow it up, but will accelorate wear, I'd shoot standard wadcutter target loads. You will be surprised at how accurate & fun they are to shoot.
For defense I'd carry Buffalo Bore's .38 lead SWC HPs in it if I were you. They make a non +P load that they claim gets 850fps. The BBl length isn't stated, but I chronographed them & got 870fps & that was from a 2" gun. The load I use says non +P right on the box. The HP is almost big enough to drink coffee out of, it's an impressive load.
Enjoy that nice old gun.
Frank