Really doesn't make much difference. The heavier one is probably going to be easier to find a accurate load, with a wider window. Check the nose diameter of your bullet in the muzzle of your rifle. It needs to be a firm push fit and engrave lightly. If not it'll likely not shoot all that great. Those Lee moulds are known for small bore ride noses, and Marlins for large bores. You might want to check out Ranch Dog molds. He has a very superior design to either of those Lee ones, and they're on Lee blocks so are cheap to buy.