Why has no mfg come out with a short barrel bolt action 45/70? Is there anyway to take a ruger M77 and make it into a 45/70 bolt action? Would I use a 458 Win Mag or 458 LOTT -M77 African model and still be able to use the barrel? What's the least expensive route?Not a mauser.... I'm looking to do this on a Ruger 77 action or a Remington.