If I had a choice I's stick with a 308 diam bullet rather than the 312 of a 303. A 30-40 fits the bill! But DR's are regulated with 1 load no matter the caliber. The current exception is the newer ones with the adjustments at the muzzle. I haven't played with them so within the pressures allowed they can be hopped up a bit more.

"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand