My Krieghoff Ulm Primus 9.3X74R double rifle is equipped with a set of combination gun barrels: 16 gauge over 7X75R SE vom Hofe, a sort of rimmed 7mm Remington Magnum. I have had a K&S full length insert barrel in caliber 6X52R Bretschneider fitted. The 6X52R lies between the 5.6X52R (22 Savage High Power) and the 6.5X52R (.25-35 Winchester). It is thought of as a roe deer caliber, but is certainly capable of killing a white tail, as is the .22 Savage High Power. This combination gives me a more or less classic Bergstutzen to supplement my double rifle and the additional set of 16 gauge shotgun barrels.

K&S (Keller & Simmann) http://www.einstecklauf.de/classic.html make full length insert barrels in calibers ranging from 17 Hornet to .45-70 Government. The point of impact is adjustable from the muzzle, so the two barrels can be made to shoot to the same point of aim at a given range. I find the combination ideal for my deer stand, with one caliber for close range and the other for longer range. If I were still able to walk any distance, it would be an ideal still hunting or stalking rifle as well.