Is this Val?

In discussing US Military 22 caliber Krags, differentiate between ordinary rifles fitted with Stevens-Pope barrels (high demand collectors items if in excellent condition) and the less desirable Gallery Practice Rifle (GPR).

GPRs come with two types of barrels.  Early production (?) has .226" groove diameter, 18" twist and were chambered for the .22 Extra Long rimfire.  Why that was done only the military mind can explain.  They function with ordinary .22 Long Rifle cartridges but are not very accurate.  They are surprisingly accurate with CCI Stingers and similar hyper-velocity rimfires, but that defeats their purpose.

Later GPRs are reported to have been made to conventional .22 Long Rifle groove and chamber dimensions.  I have not seen one of those.

The challenge with a replacement barrel would be fitting an extractor.  The extractor on the Krag bolt grabbed an auxiliary extractor.  The aux. extractor is what pulled the cartridge case out of the chamber and deposited it inside the Krag action.