What Kilotanker22 said, last fall my son bought a 300 win mag from one of his friends without even shooting it or mine. I have one, rem 700 bdl. I bought a scope for him after I could not talk him out of it. he bought two boxes of large gr. bullets and headed out to sight it in. When he came home with a bruise on his sholder and the gun still not sighted in, I asked him to let me help him.
We bore sighted it and took some lighter rounds and finished sighted it in.
Point of story, I love the 300 win mag. great long range gun for 30 cal but in heavy weight bullets can be punishing and expensive to shoot unless you reload.