So I have a 7mm rolling block that needs a barrel a 1:8 twist .308 pac-nor blank and I need to decide on a chamber. Was hoping to have a cast boolit gun that would mostly be downloaded for woods walking and small game , but one that could step up in the fall for migrating caribou. It is kind of of short list due to pressure concerns on the old action, but 30-30, 30-40 and 300 black out have all crossed my mind. Anyone have any strong opinions ( 30-40 makes the most sense but I have no brass and it is not cheap or common ) 30-30 I have brass and other guns for and black would be kind interesting in a single shot and may by virtue of its smaller case be run at higher pressures...but may be out for open ground hunting bigger stuff .....probably a 6.5 swede or even a replacement 7mauser makes more sense but my normal suppliers are out of stock and lead times are and issue.