Worst case scenario with both calibers not opening up at all is you still get a bigger diameter hole with the 308. From your choice of rifle, it does not sound like there are any financial issues to consider as in cost of rounds, etc. And it sounds like you're hunting locally so are not worried about whether you can find ammo on the road, etc. Since you're looking at closer ranges (20-200 yards) are there any brush busting issues to consider?