I had a thought. A J frame is smaller than a K frame and with rounded grips is a lot smaller weapon than the K frame Smith.

One last thought on this yes a semi-auto would be a good self defense gun but I would practice a lot on using it in an emergency situation. Being this is emergency gun watching out for reloads which can gum up your gun and void your manufacturer warranty. I think the practice required to use an auto should be a lot so that a beginners movements with the gun are automatic. I would use factory only loads for self defense as well as cleaning it after every shoot because you can't afford to have the gun jam or malfunction in an emergency. I know I am going to get some flack about this but if this is your emergency gun be very careful about the reloads you use. Personally I wouldn't practice with reloads myself with the emergency gun. Practice turning off the safety and pulling the slide back to get a round in the chamber. I will say the amount of practice required to be able to use a gun in an emergency is more with a semi-auto than a revolver because before you shoot you have to be concerned about a round being in the chamber, the safety being turned off, the ammo you are using, your gun jamming, and the forgetting of one step could cause your gun not to fire in an emergency. When your life is threatened you aren't going to be thinking very straight and it can become difficult to remember things when in the fight or flight response to danger. The other thing assumed by a lot of people is that the attacker is a blithering idiot that knows nothing about guns. Don't assume. Psychopaths are know to be extremely intelligent and often have a very high IQs.