Have acquired some New Old Stock (30-06) barrels made for the FN 98 actions with Sq. Threads, 10 TPI.
Said that the idea was to utilize the readily available 1903 Springfield barrels available at the time. (These are not 1903 barresl)

Looked up the minor thread diameter of the 1903 square threads.

At .990" these barrels could be used on a small ring Mauser such as a 98 Turk.
The one 30-06 Turk I worked on was wee bit short for .30-06 and limited to short seated 165gr boolits.

Questions:

How much needs to be trimmed from the shank to rechamber from 30-06 to .308Win?

Or .300 Savage? Trim, light barrels that would work nicely on a 1910 Mexican Mauser action.

Need these numbers to see if enough chamber area of the barrel would remain, or if they need to end up on eBay.

Thank you for any help.

I'd say around .4" for the 308 and .46" for the 300 savage. That gets you to the neck shoulder junction so maybe a touch more to insure you clean it up.

After looking at case dimensions I was 'guesstimating' that 1/2" should do it.

Have never set a barrel back for a different cartridge so looking for some experience to double check.

I appreciate the numbers. Thank you.