hi
there are some barrel makers in Germany making very nice insert barrels in a great variety of calibers. back in early 70s . i have tried a friend's gun with insert barrel in 22 caliber hornet and was amazed of it's accuracy. these insert barrels are made up to 9,3x74 and even larger caliber . does anyone tried to convert his doulbe shotgun to a DR with help of insert barrels?
cheers
yes

I can't imagine how you would regulate the barrels with inserts, short of unsoldering the ribs, and fabricating a regulation wedge. Someone please educate me if this can be done.

Turn the insert barrel undersize for the host barrel. Install a bushing at the muzzle with an eccentric bore in it. By rotating the bushing you move the point of impact. When regulated, you lock the bushing in place. The downside is that you have a .22 Hornet say, whose barrel O.D. is that of a shotgun. Not very aesthetically pleasing and unnecessarily heavy.

Most all of the full lingth einstucklauf have regulation adjusment built into them.

frankonia is selling them for about 750-800 euro and they are made of german coldhammered stainless steel i am going to buy one in 30 R blaser or 9,3x74R. for my /U combo.