From some research online it seems these are much easier to rebarrel then the K31 or K11.
That's what I've heard; they're similar (except with weird threads) to rebarrelling a Mauser. A rebarrel to 7.62x54R and 30-40Krag apparently requires little work other than the barrel (can still use the clips).
I'm looking to rebarrel one of these to glorious .50 Alaskan. Some weeks ago I was did the research for the bolt thrust calcs over on THR; you may find the info useful:
Chamber Pressure in Regards to Cartridge Selection
(sent money off for cheap used dies today, and will be buying a cheap 50cal blank soon
The main thrust (
) of my math was that choosing a cartridge with a lower pressure than the factory is the best bet (even if caliber is going up some). In the case of the .50AK, the larger bolt thrust area is offset by a much lower pressure. These are sturdy actions, successfully chambered in 8mm Mauser, and moreso in the extremely potent 8x56R cartridge, and if you keep your pressures and bolt thrust below those, you will be safer than the unaltered configuration. (I will be testing my model with a vice and string the first few times, though