Krags are nice rifles and have the smoothest, bar none, of the rifles in my collection. Don't have a Mannlicher Schoenauer to check it against.
Grafs and sons does have the Krag brass while Remington has done seasonal runs of their 180 corelokt krag ammo during hunting season. Did not see any this year so Remington may have discontinued the ammo. I suspect the source of the Krag brass is Prvi Partisan which makes some good brass for reloading and it may be altered from their .303 brass. Checked my brass stash for reloading and the Grafs krag and Prvi .303 have the same rim size but the Krag brass has an extractor groove which my .303 does not. BTW, for reloading, slug the barrel, Krag barrels vary much more in bore diameter than 1903 barrels with some approaching .310-.311.
The cracks in the bolt lugs have been generally blamed on attempts post 1898 to get the Krag to fire hotter ammo and the use of cupro nickel bullet jackets which generated pressures beyond the Krag's design. Apparently the bolt problem was common enough to generate a lot of surplus bolts floating around. Even just recently, you could find a stripped new "old stock" factory bolt that had never been used for about $50 dollars. Others have addressed how to check for cracks but there is also magnafluxing if you have friends in the automotive engine repair field. There are also some parkerized Krag bolts floating around that reputedly date from WWI usage but that is just anecdote.
New barrels are available from Criterion and Numrich both in carbine and long rifle length. Criterion's are in the white and the last time I checked, Numrich's were blued.
Keep the loads down, shoot lead bullets, and if your Krag is in good shape, it will last a lifetime.
