The gun was done by Norm Hamm of Sundridge Ontario many years ago. He fit the new model winchester model 64 Barrels to a mono block that he built. It has extractors and shoots real well. He regulated it with Imperial Ammo that is not made any more so I handload for it. Mr. Hamm also made a 25-20 double on a 410 but I have been unable to find it. He made actions of his own design including single shot break open and a small bolt action. You will notice that there is no rib between the barrels. It looks different like that but as I recall there was an English maker that did not have ribs. The 20 Ga. barrels are intact and I have never shot them.The firing pins are bushed and the gun has a single mechanical trigger. In the photos you can see where he fitted a tappered ring between the mono block and the barrels to make the taper. The bluing is mostly gone in that area. I have tried to touch it up but is does not seem to take on the rings well. I have tried several kinds but have given up. Prior to Mr. Hamm passing he was looking for a certain Beretta sxs shotgun that he was going to make a 303 on.