I like the 45acp and figure if the answer to the problem takes more than 8 rounds then I should have grabbed the shotgun or the AR. If you're not a reloader and want high capicity or to shoot alot choose the 9. Otherwise go for one of the larger bores. Some of the newer 9mm self defense ammo is rated very high as a fight stopper but you'll pay a very high price to practice alittle with it. The 45 bore has been TCB for over 100 years now. TMSAISTI.