Maybe the photos will explain it better than 1,000 words. The barrels came from Numrich Gun Parts maybe 15 years ago and probably are no longer available. The 30/30 barrel was originally made for a levergun Mossberg offered for a short time maybe 20 years back. The .22 was intended to be the upper barrel of a savage 24 but was a reject because the bore was off center at one end. I used a stub of an H&R 12 gauge barrel and turned the 30/30 to slip into the 12 gauge chamber, the shoulder of the 30/30 barrel abutting the forcing cone of the 12 gauge. The H&R underlug is longer than a Savage so it was shortened from the front end until it would seat and lock up in the Savage. The .22 was soldered into a groove filed it the top of the H&R barrel. The 30/30 was pre chambered but I had to rent a reamer to chamber the .22. I used a front barrel band for an M-24 .22/.410 and it just happened to fit both barrels perfectly. It took some trial and error tinkering (lots) to finally get the .22 zeroed at 75 yards when the 30/30 is 2" high at 100 but there it now stands, finally! One of the most frustrating parts was getting the .22 extractor to work, I tried several designs before finally getting one to work without binding. I did this while living in a 2 room cabin, my only tools being hacksaw, files, a bench grinder and a propane torch.
Of course it would have been much easier if I had started with a Savage barrel stub but I had the H&R and I wanted to preserve the original .22 mag/20 gauge so I now have two sets of barrels for it.
