I have a "switch barrel" set, consisting of a Krieghoff Teck (box lock) O/U double rifle in .458 Winchester Magnum, with interchangeable barrels in .375 H&H Magnum and 20 gauge 3" Magnum.

I have on order another Krieghoff Teck in .500 Nitro Express, with interchangeable barrels in 8X75RS and 12 gauge 2 3/4". Also in the works are a Krieghoff Ulm (sidelock) O/U in 9.3X74R with barrels in 16 gauge 2 3/4" and another Teck in .450 C&W (.375 H&H Flanged opened to .458") and 12 gauge 2 3/4".

Obviously, I'm enamoured of the concept.