Guys

If I had a LH M70 in say, 300 win mag could I switch out the .532 bolt with a .473 bolt plus the magazine and barrel and have it run through the receiver just fine?

Maybe, maybe not. The wider mag rails might be an issue keeping rounds in the magazine.

It would be a 30 06 based magazine as well.

I'm talking about the feed rails milled into the receiver.

Sorry. Can those be remachined for a different, smaller cartridge?

The feed rails can't be milled narrower. If they won't hold the rounds in, the only option would be to weld them up and re-machine for the smaller round. You can test it ahead by installing a '06 follower and mag, then seeing if it will feed and hold the rounds in. Far less trouble and expense to find a LH .473 rifle complete.

Thanks!

Not pretty but can it be converted to a detachable mag?

Oblivious of the face width, do M70 bolts tend to be so similar in distance to the rear of the lugs that a lost one might be easily replaced?

I'd previously thought bolts were a bit like keys, not often interchangeable without headspace considerations.

Hold the phone!
Standard cartridges feed fine from post 64 magnum actions; I use them interchangeably.
And I just loaded a mag full of 7.62 Nato (they were handy) into a 7mm Mag and they fit and fed fine. Also remember that post 64 Model 70s use the sheet metal mag box lips for feeding control too.
Try it first before you discard the plan.

quote:

... Also remember that post 64 Model 70s use the sheet metal mag box lips for feeding control...

This. Beat me to it.