I have a set of WW. Greener 375 double rifle barrels. I so happen to have a Imman Meffert 16ga that has the cross bolt and double bite as the rifle barrels. I know the lumps would need to be fitted to action and the overall width of the shotgun breech is larger. But not by a whole lot.
Fitting a set of double rifle barrels to an action requires that the Circle of the barrels fit firmly against the Draw of the action when the barrels are closed with the action. If you know that and have considered and thought out how you are going to do that with the .375 Greener barrels you are probably ready to build a double rifle. If you do not know how to fit the Circle to the Draw you should read about the Circle/Draw subject in Vic Venters gook "Guncraft". It is not a task for the faint of heart.
Kind Regards;
Stephen Howell
