mikelj:
It will come as a shock to some, but back in 1905 there were bad guys, that got shot by good guys, using the standard .38 Special load of the day, which made them into good/bad guys
. (Of course it sometimes worked the other way around too).
Anyway I suggest that since your revolver doesn't have a heat treated cylinder, you consider using .38 Special 148-grain mid-range wadcutters. This is by no means a high pressure load, and roughly duplicates the .38 Long Colt and .38 S&W cartridges, but with a much better bullet profile.
What is more likely to stop an attack is not so much the latest super-zinger/hollow point, but rather placing the bullet precisely in the opponent's body where there is a vital organ. When it stops working the assault will also.
Of course there are better handgun/ammunition options, but I'm going to presume that for whatever reason those choices aren't available to you. Take heart in the fact if your old revolver did the job back when, it probably can do the same today.