I don't say this to be rude, just a point of fact. As others have said, if you have to ask than you probably should not be shooting much over 200-250 yards. Keep in mind "Most" hunters will run out of skill long before that 7mm Mag will.

I say this as a seasoned hunter with limited time to shoot a lot myself. For me 300 is a long poke, but do-able, even then I would just as soon get closer!

"Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything." Genesis 9:3