Back in those days, I would think there was about 80% chance it would mostly be fired with standard pressure lead roundnose bullets. If you inherited it, do you consider it an heirloom or trading stock? Cause if it is a nice Colt, it might bring some bucks and then you could get a more modern Smith with the money, like a model 10, or 64, and shoot +P as you wish. If it is an heirloom, you don't want to break anything, or just make it looser and not as nice as when you got it, from firing alot of hot ammo. If it were a crisis and you loaded +P ammo into it for SD, I suppose you could get away with it, but I assume this is not a primary SD revolver, so baby it. Colt repair men are getting scarcer and expensiver.