In a #1 I'd go 45/70. I have ran 350g Hornady flat noses up to 2100 fps in my marlin guide gun. My gg is not ported though and as I've gotten older those loads are too much. Lately it's been cast and powder coated lee 340g at about 1600 fps which still kicks a bit but doesn't stand the barrel straight in the air. Generally I think there are more options in factory loaded 45/70 then the bushy although during this last shortage bushy was easier to find. If you handload the 45/70 is very versatile. There are some decent cheaper bolt guns available in the bushmaster that may be worth a look.
I fought with a 458 socom for years but always had some type of feeding or ejection problems. The dies and chambers of the socom are often spec'd different. Radical took my 458 upper back and gave me a 350 legend rifle upper along with a 300 bo pistol upper for my trouble. The 350 functions well but I have to watch for setback in an ar.
Lately I've carried my 444p marlin outfitter more than anything. Those ports really help for quick follow ups and my moderate load of 270g Speers at 2200 still seems like enough for most things. If 444 is an option the factory 265 Hornady flat nose does a lot of things well. I'm not sure if a #1 is available in 444 though.
Bb
