theory.....i don't do .40 as in stock up...but if I see a .40 that i just wanna carry.....a box to shoot it..(if a glock, one box is good.)...a box of self defense ammo , I am good for the purpose of the gun...that explains my shield .40..lol....and why I am thinking on 357 sig....the Shield 45 shoots amazingly, carries easy, but that dang sp101 feels so good in the hand...someone buy it!