Well, you have a nice rifle. However the weatherby rifles have never been known for their accuracy because of excessive freebore. The bullet jumps to the lands and the distance it jumps in a weatherby is totaly to much for an accuracy stand point.
Some do shoot well but a factory weatherby with a factory barrel will not get you what your after.
Some may disagree but I have never seen one shoot moa or even sub moa with the best loads and best bullets.
You may be able to use it as a single shot because youll have to seat the bullet out so far to engage the lands that the magazine well will not hold them but I doubt it as the bullet shank is short on sierras and the likes, but if you used say berger, jlk, or lost river ballistic bullets you may just be able to touch thoses lands.
Your twist will determine a lot of what will perform in your gun also. Heavy bullets do well with faster twists, and the reverse lighter with slower twist.
This 30-378 is a barrel burner from what Ive been told and read about but since you have a weatherby you may see a few more rounds than a custom barreled rifle would because of the freebore distance.
Try this link may help you out a bit.