cable,
I must admit I am prejudiced against rechambering these fine old guns and believe they should be preserved when possible( I'm a wildcatter on the other hand). It is not my gun, however, and as long as I insist on being the one that decides what happens to my guns, I have to say you have that right too. Alaska is full of 22 Hornets, but I doubt if there are very many 5.6x35Rs there. European 5.6x35R cases will work without modification, European Hornet cases will not. The 5.6x35R is pretty rare in Germany now and if cases can be found they may be Berdan primed. I load with two different size Berdan primers, but I'm not sure if you can find the size required for this cartridge. Thinning the Hornet rims from the back and deepening the primer pocket with a primer pocket uniformer is pretty quick and easy, and wipes the incorrect headstamp off at the same time. Thinning from the front would require making a spigot to locate and hold the cases to reach the front of the rim. To be efficient, you would need a lathe for either method. A lathe ( and mill) is a requirement of life any way. You can buy cases already modified, Bertram might make new ones, or you might have a machinist friend that would do them for you if you can't do it.
You should be able to have a set of "Tip off" rings modified to fit your base, if you can't find a set with the correct size dovetail. If you buy a set of extra high rings, there should be enough room to mill the bottoms off and cut the correct size dovetail and relocate the clamp. You would bump the front one against the buttress at the front of the base, and "stop" the rear one with the groove in the base.
The "mission" of the 5.6x35R has largely been taken over by the 22 Hornet, 22 Magnum Rim Fire, and 17 Rim Fire Magnum, so un-molested guns are getting harder and harder to find.
Mike