The post 855,000 barrels simply use parallel V grooves, which allows barrels to be swapped back and forth. Other good gunsmiths if they take the time to understand the dimension relationships could do them also, but they have to take the time to look at the design. A person has to understand the dimensional relationship before hacking away at the metal.Īs I posted, there are 2 gunsmiths that I know of that I would trust to fit the barrels. To fit a barrel, the barrel face and the shoulder have to be carefully machined on a lathe a little at a time until the barrel will go into the receiver, start into the threads and then when turned, bottom out with the all the aforementioned features in alignment. A 1/4 turn does not translate into much movement, but it is there and has to be taken into account. If they do start, they will usually stop before going into position.īecause the threads have a 'pitch' to them, the barrel is actually pulled into the receiver a small amount, just like a bolt is pulled into a nut/threaded hole when turned. You can fudge them by backing them out a little but then they won't headspace correctly. The witness mark allowed them to align the barrel in fixtures to cut the thread interrupts, the extractor cuts and to put the barrel lug on. If you look at the older barrels most if not all will have the witness mark.
In order to fit the barrels (from what I can tell by observation and talking to other folks) the barrels were screwed into the receivers and a 'witness mark' put on them. There were also Skt marked barrels (or maybe nbr 5)
#Ithaca model 37 serial number dates full#
Ithaca choke marking system: '1' for Improved Cylinder '2' for Modified '3' for Improved Modified and '4' for Full choke.
#Ithaca model 37 serial number dates mod#
Such as 543123-2 indicates a MOD choked barrel. There will be a serial nbr on the front face of the receiver, running vertically next to where the barrel goes in, and the serial nbr on the barrel that also has a - (dash nbr) to indicate choke. This is why the barrels are serial nbr'ed to the receiver. Much of the data presented for the Model 37 guns came from microfilm copies of Ithaca. There is a dimensional relationship between the barrel face, the shoulder at the end of the threads, the face of the receiver and an internal shoulder. Unique serial number sequences were established for special edition and commemorative Model 37 and Model 87 guns. The older barrel threads (pre-855,000) had a pitch to the threads, just like on a bolt. The newer POST 855,000 barrels are interchangeable. Is there any truth in what he says or has he been miss-informed? He says that pre-855,000 guns are interchangeable with other pre-855,000 guns based on how old your barrel and shotgun are, but I have heard this is false from a variety of forum members and old timers at the gun club.