RE: BLR Caliber
I was very impressed with my friend's BLR in a .300 Win Mag. It fed smoothly and reliably and he was amazingly accurate with it even with iron sights. Sounds like the recoil may be more than you're after though. I'd go with the '06 and use lighter loads in it when you want or go "loaded for bear" when it's fitting. You can't beat the versatility of an '06.