Mike, the Slug barrels you mention are very hard to find. I have one and have been in contact with 3 other people who have one. One of them has the placement of the rear sight in a different position, but otherwise all are the same with no markings other than a "20" in a circle on some and just a plain "20" with no circle as on my barrel. As to other barrels, they are plentiful on Ebay, but you need to be careful which ones you buy. While they all appear to be the same, they are not. The early model barrels, First Model Utica, Second Model Utica, and the "A" suffix barrels may fit the late guns, but will not work on the "B", "C", & "D" suffix models as they do not have the cocking stud on the rear of the barrel lug. However, all these B, C, and D barrels will work on the early guns. Also, you have the risk that the newly purchased barrel may not fit properly and will require a gunsmith/machinist to fit it to your action. I removed a .22 Hornet barrel from a outside hammer gun and it fit perfectly on a M220, 20 gauge gun that I had. However, with two other barrels I purchased, I had to try them on several of my guns before I found an action they would perfectly fit. On some they would not close at all and on others they would close, but had a gap between the end of the chamber and the frame. I hope this information helps some and is not too confusing. I'll be glad to help in any way I can. If you will send pictures of your friend's gun, I will try to identify it for you. Best wishes, Garnett (click on pictures to enlarge)
