Does any company make a bolt action 45/70 govt. I was just thinking in a single shot rifle it can be hand loaded up to a 458 win mag and in a modern bolt action the same could be done with the advantage of it being a repeater.

in my speer manual they are listed by type of action, springfield action being the weakest and modern leveractions win 1886 and marlin guide gun and then modern single shots example ruger #1, I think the New england arms handi rifle would be included in this. the stronger the action the hotter the recomended loads

The Gibbs rifles based on the British Enfields are chambering for the 45-70 the examples I have seen are somewhat rough but functional and very affordable. The 45-70 is a very strong cartridge in modern rifles and handguns allthough it can't begin to approach the 458 Win Mag( neither does the recoil) it can approximate the 458 American (458 x 2). I have seen a BFR revolver chambered in 45-70 chrono at a bit under 1700 fps with a 470 Gr. cast bullet, and a Guide Gun with the same load hit a bit over 1700 fps. This is plenty strong for anything you should encounter.
Have a nice day, Rabon...