In general... the heavier the bullet the better it will DROP the animal "on AVERAGE" that is not to say that a top notch marksman w/ a 243 wont do better than a goofball w/ a 375 mag. But on average the bigger calibers will do you better, 270, 264win, 280, 284,7mm's ect....308 30-06. I have used a 300win mag since '92' and have not had ANY deer go more than 2-3 steps. By the same token... I used a 6mm for years and never had any lost animals, but they did go a little ways. My son uses the 6mm now and he dropped his 3X4 mulie this year on the spot, and last year his 4X4 went 20-30yds.