Main problem with HP22 is its safety

The thumblever needs to be moved .5" to the rear, so that the ball of the thumb can manipulated it easily, without your having to "shift" your hand out of a firing grip.

The safety really DOES block the sear, and there is an external hammer. However the safety is made of pot metal, even the part that bears on the sear, so it will wear to a dangerous level in short order. Making and fitting one by hand, and then hardening it, takes at least 2 hours, and might take you three. That adds $50-$100 to the cost of a $125 gun.

The safety on the slide is best just Loctited out of commission. The "adjustable" rear sight flops around on most HP22's. So after you get it "adjusted" so that POI coincides with POA, loctite it,too. It's a pointless PITA, having to engage the safety to move the slide or remove the mag, so it's best to grind off the parts of the safety that block those functions.

Spare mags are $15, and a spare, 5" long barrel is $40, so you can have a 3 3/4" long barrel, with the protruding 3/4" being threaded 3/8x24. All in all an intriquingly useful little gun.