AS a Firearms Dealer I can tell you that the 45GAP Ammo is expensive. You definately will not be buying 45GAP ammo at Walmart. I would also look at the ballistics of the 45GAP compared to the 40 S&W. Corbon Pow"r"Ball ammo 45GAP 1075fps - 424ft lbs, 40S&W 1325fps - 526ft lbs. The 40S&W is faster and has over 100ft lbs more kenetic engery. More kenetic engery equals more stopping power.