Hello I have a rifled, but unchambered CM barrel in 375 caliber. what is the minimum chamber wall thickness? at just under 1 inch diameter, with a half inch brass cartridge, I have less than .300 inch in metal on the chamber walls on this barrel. Either need to look for a different cartridge 375X62? or sleeve down, or what? build a pistol cartridge rifle?

btt

That 1" measurement only relates to the diameter of the threads correct? What is the diameter of the rest of the barrel over the chamber? What action are you putting this on?

With a good action, a 1" diameter threaded tennon is sufficient for the .375 H&H round because the receiver would make up the difference. The diameter of the barrel over the shoulder, neck and throat area of the chamber are what you should be looking at.

If on the other hand the entire chamber area is 1" in diameter, use it for a tomato stake.

Not the entire chamber area, just the front inch or so ahead of the threads, where the narrrow cylinder transitions down to the featheweight style barrel taper.