I know it is not a big bore but have you considered the 6.8 SPC? You can load bullets from 85 grains to 140grs. in it and speeds to over 3000fps. It is becoming one of the most popular rounds for hogs and has been used to take game from varmints to elk. Barrels are available from some of the top builders now, I have bought three in the last few months. If you want to learn more go to the 68forums website, some of the most helpful people in the business.