I have a Navy Arms rolling block action.I am planning on putting a .45-70 barrel on
it.I am planning on using the 300,the 400 and 500 grain bullets.I am also planning on this one strictly as a blackpowder rifle.Would a twist of 1 in 20 be good or not.Would like to get the most accurate twist as possible.Planning on at leasta 28 inch barrel,havent figured out if it should be octagon or round,and what was the carbine/cavalry load