If one was to have a 458 Win mag in the model 70 what would the biggest rechamber be for that action. Not a rebore just a rechamber and bolt mods and action work to make it feed. I know the Lott is the easiest but I was looking for a bigger case.
Thanks

I have seen several 416 Rigbys done on the new classic action with a custom magazine. The action is opened up to the rear and the bolt stop and ejector modified. If that can be done then the 450 Dakota is just a rechamber away.

The Winchester model 70 was not originally designed to go larger than .532" cartridge dia or boltface. I know this has been done in the past, but I don't see it as a good idea with other options available. Problem is there is just not enough barrel material around the thread shank for much larger cartridge. Check out the .458 AR it should clean up the chamber or if your action is long enough for something different the .450 Watts. .458 AR, 500 grains at 2,300 fps in standard length action, kind of tough to beat. Rodney.

Well I will have to disagree with the above post. I've seen everything up the 585 Nyati done on a Win Model 70 action that started life as a .458win mag. The differences between the std length and magnum length actions are actually minor. The biggest issue is the mag box mods and feeding ramp changes that are required. IT would not be my first choice for anything bigger than a 458 Ackley or 450 Dakota IMHO though. Our own 500grs once hunted Africa with a 585Nyati built on a Win Model 70 action. I've built 450Ackleys and a 470 Mbogo on one. Basically you can go as big as your wallet can stand.-Rob

If you go bigger than the Ultramag case head ~ .55" in diameter, I strongly recommend that you open up the threads of the receiver.

ScottS-What would you know about opening receiver threads? Didn't you just tell us you Buldged the chamber of your new .458 win mag with your stupid reloads? Still waiting to see the pics. -Rob

Rob,

I wouldn't know anything about opening threads. I'll leave that to an expert like yourself. I only mentioned it to try and be helpful. I think I read of it in a gun magazine once upon a time.

a rigby case will have feeding nightmares.

the barrel is what, 1x16 threads? same as the ruger and remington? can do rigby sized cases, no problem..

to answer your question
for the best resale, rechamber to a Lott
for the least work, rechamber to a 458 AR
for the most work, most powerful for that one, 460 weatherby (wow, there's a nightmare)

of course I would recommend the 458 AR.. rechamber and go

The .460 bee would be the biggest case.