I would buy the HP and see if it feeds reliably enough, and then hope & pray you never need to use it for defensive purposes. I almost think you would be better off with a knife, becuase the effective distance for use is about the same IMO.
I had a .25 auto for a few months, I got it in a pawn shop for $30.00 back in the early to mid 1980's. I got rid of it shortly after I got hit with a ricochet from the gun, I was shooting an empty55-Gallon steel drum and the .25 would not penetrate it, the round bounced back and smacked me in the back of my hand and left a hell of a bruise. I also got hit in the legs a few times.