CTB is not easy. It's hard to kill yourself, and particularly hard to get past SI. That being said, many people have CTB with a 9mm gun. Where are you planning on shooting yourself, as far as placement on the body? If I were going to CTB with a gun, which I'm not, I'd go with the most powerful 9mm ammo I could get and hollow points. And I'd shoot myself through my mouth in order to take out the brain stem. You really should be asking this kind of stuff in the Suicide Discussion Forum. You'd get a lot more responses.