I'm getting ready for my first caribou hunt and am planning to hunt with my trusty 25-06. Someone insisted I should stick with 117 grain bullets, but I got the 100 grain bullets. The store won't take ammo back and the best that I can understand is the grain measures the "punch" of a bullet, so how different are these grains? Okay to hunt caribou with the 100s??? I don't intend to take a shot at more than about 100 yards, cause that's where I'm comfortable and consistent, if that makes a difference... Thanks for any knowledge or thoughts!