I don't know what a big 7mm will do that your .300 will not. I would go with a much lighter caliber, either .243 or another 6mm flavor that will doing the high BC slugs at 3000+fps.

Hunt hard, kill clean, waste nothing and offer no apologies.

"In rifle work, group size is of some interest...but it is well to remember that a rifleman does not shoot groups, he shoots shots." Jeff Cooper