400 or 405 grain bullet loads are better for hog. The 300 grain loads are a modern deer hunter's load, to reduce recoil and flatten trajectory. The 300g loads are more lightly-constructed to expand on deer.
If the 300g loads were all you had and you had no chance to improve upon them, I wouldn't wave off a man from hunting hog with them. But since you're outfitting yourself with a task-specific rifle (great choice) and loads in advance of hunting, why not get the more optimal loads? I'm not saying that you need to go buy some $50/box loads of Buffalo Bore or Garrett cartridges-- I'm just saying that you'll get better penetration with the 400 or 405 grain loads.
Don't forget to sight-in, and practice from field positions!
Do you have a good receiver peep sight installed yet? If not, may I suggest the XS (formerly Ashley Outdoors) peep sight? The thing is bulletproof, mounts on the extant rear scope mount holes, and improves accuracy quite a bit without compromising speed.
Good luck.