A three hundred yard shot is not a problem for an 06, however, if you are going to shoot at those kind of distances you need to practice at those kind of distances. Just for the fun of it, set up a gallon milk jug full of water at three hundred yards and see what happens. If you can't bust the milk jug consistantly, then the odds are you will either miss a deer or only wound him and never recover him. When I was hunting with a rifle I always set up my 06 to be .7 inches high at 100 yards, that put it dead on at 200 and about 5 inches low at 300.