If you're shooting for sport, use what ever the hell you want. If you're shooting for survival, shoot the commonest calibers. 9mm, 45 acp, 223, 5.56. .22 for food. And 12 ga. You want ease of resupply. I try to get famiky to buy the same calibers so we can cross supply. The women get 380' s for self defense. Before the feminazi's start barking, they can shoot my 45's if they wish. They don't. I do have a 22 that I have tinkered with that they all LOVE, but they ain't getting that.