That's why I asked the question. If I were using it for SD then I would want the most responsive gun I had. In this case the 45 would be my selection as less recoil quicker back on target, more comfortable to shoot. One thing going for the 40 was it seemed whenever I was looking for ammo the 40's were most always there. Have said this I'm a firm believer in a guy or gal shooting anything they want to shoot. I'm only thinking out loud reason why I would pick the one over the other. Again, not critiquing here just my thoughts. BTW I've not shot a 40. I've read up on all the Kahrs though and specifically the 40. I've also stayed at the Holiday Inn......grin.