I am happy to reappear. have over thirty US Krag sporters, all in "big game" calibres, .25-35 to .405 WCF, allrepeaters. They range from simple cut sown militaries to custom jobs from several of the famous interwar makers and a few known contemporaries. I have never been able to corral a G&H .30-40 although I do have a .25-35, Michael found it in a G&H used gun list from the 1930s. There are quite a few G&H SS Krag varmint rifles, I hear of one or two a year, but have never run into another repeater. If you had a few hundred bucks to spend on a hunting rifle at G&H in those days you either joined the NRA and bought a 1903 or used an Oberndorf 98, notan obsolete old Krag.
At any rate, there are a few Krag fanatics left and I seem to be one of the leaders. At the moment I am away from home without acess to my lihrary or the guns themselves so I am speaking from memory. First, both .405 and .35 WCF in factory loads are too hot for the Krag. The issue is academic for the .35 since there has been no factory ammo for more than fifty years. It is also too long for the magazine box, on
my rebored rifle notwithstanding grinding out both ends of the magzine to the max the factory loads need bullet noses trimmed what I remembher by .06". I think the box on my .405 needed a little work but it wasn't much. The gent who had the rifle built took it to Africa. The pressure problem is readily solved for a .35, you would have to handload anyway so make a .35 Krag wildcat. On a .405, one should take advantage of factory ammo and strengthen the action by setting up a rear locking lug like a Norwegian or Deanish Krag. The rear of the front locking lug can be ground off to let the bolt set to the rear if you are rebarreling. Or the front of the receiver "bridge" or the rear face of the bolt rib can be built up by welding. This last method has been used on several of my rifles including the 405, no other work was needed when I had this done the previous custom work could be left alone.
Krag bolts are in good supply and if yuu spoil one it's not the end of the world. One caveat about this double lug conversion, it's asymetrical. The Norwegians found in their rifle matches that in rainy weather the zero changed and a lot of their ranges were made with covered firing points to keep the rifles dry.