Navy Arms used to sell Mauser Rifles with the chambers bored out to .45-70, and a heavy new 45-70 barrel. You could order extended 45-70 brass which effectively made the hitting power of the rifle like a large caliber Weatherby magnum. A moose hit in the shoulder would be rolled right over , legs up , almost before it hit the ground!
Nice rifle! Nice caliber!
Had a gunsmith friend build one for me over thirty years ago, using a Santa-Barbara Mauser action and a Douglas barrel. Cast the bullets, loaded my own also. Used it on wild pigs in the Savannah, GA area while living there. One-shot stops. Works equally well on deer.
Now the recoil is too much for me. Fun while it lasted.