View Full Version : Ithaca Model 37 barrel swapping
April 29, 2002, 01:40 PM
I have recently purchased an Ithaca Model 37 16g, serial number 135XXX (IIRC). Date of manufacture should be 1947. I want to switch out the bbl (OEM), but I'm sure you're all aware of the difficulty I'm having. ;)
The problem is with the pitch of the threads between bbl and receiver, no? How hard is this to 'fix'? I have a good price on a barrel, but after I add in the price of gunsmithing, the price might not be so good. The barrel seems to almost seat, but the thread pitch seems just different enough that it won't go.
Any advice would be appreciated.
April 30, 2002, 08:18 AM
The Ithica uses a 20tpi thread. Anything else isn't going to work. If you're saying that the barrel almost turns in all the way but won't more than likely the shank dimension is a slightly larger than the original either in diameter or length. If the barrel was made for the 37 then I would contact the maker and see about exchanging it. If it's not made for the 37 then I'd get one that is. George
April 30, 2002, 07:56 PM
I think that your problem is related to the date that Ithica started making thier barrels interchangable. There is a difference in the dimensions of the barrel threads previous to a certain serial number, the newer ones interchange freely and the older ones need fitting. I don't know what the fitting entails. I think the time frame of the changeover was in the mid 1950s, but you'd be well advised to check that out with someone who really KNOWS for sure.
Don in Ohio
April 30, 2002, 11:02 PM
1. the bbl is definately for a model 37, 16g. Either that, or some miscreant stamped the barrel to say it was in a dastardly attempt to foil my efforts to rebarrel this gun. ;)
2. The barrel and gun are both DEFINATELY from the pre-interchangability era.
Basically, I'm asking what exactly has to be done to make them compatible. Anyone know?
May 1, 2002, 08:38 AM
You'll have to compare the old shank to the new one and see what the difference is. I would expect that the new one is either longer or slightly larger in diameter than the old one. If it's a little longer and you have to shorten the shank then you definetly need to have the headspace checked. The chamber may need to be deepened. George
May 1, 2002, 12:14 PM
Assuming that the shank length is the issue (seems more likely, as the barrel will start to thread...if diameter was the issue one would think it would not thread at all), how hard is that for a gunsmith to adjust?
I'll be checking the shank length on monday (my next trip to the gunshop).
May 4, 2002, 01:39 AM
May 4, 2002, 08:19 AM
I thought I had already answered this. Sorry. If it is a length issue then the breech will have to be faced off to the correct length and the chamber deepened to the correct headspace. Just because it will go in partially doesn't mean the diameter is correct. To illustrate, I was at a machinist's friend of mine's shop Tuesday to look at a lathe I'm considering buying and he was threading a piece and checking the fit as he went. Even though according to his chart he had reached the correct depth for the thread the piece would still not screw completely on the shaft. He simply took a file and ran it over the threads a few passes. Probably only reducing the diameter of the threads by a couple of thousandths but the piece screwed on with a very close fit. It should be fairly easy to measure the shank of the new barrel and compare it to the shank of the old. That should tell the tale. George
May 4, 2002, 11:04 AM
OK, so are we looking at modifications to the receiver, or solely to the barrel (assuming the shank length is too long)? The point of this exercise is to obtain a second barrel, so I can swap between a short bbl (cyl bore) and a long one (full choke).
May 4, 2002, 01:11 PM
NEVER modify the receiver to get a barrel to fit. This applies to all firearms and especially ones you want to use the old barrels on. If you go to Ithaca's home site and ask the question, they will probably tell you what needs to be done.
May 5, 2002, 11:28 AM
OK, that answered my question. I didn't want a receiver modification, for obvious reasons. I'll ask Ithaca to be sure.
May 8, 2002, 09:54 AM
Coronach: New Ithaca barrels for sn's below 855,000 must be fitted, indexed, headspaced, and generally are serial numbered to the frame. There used to be a fellow named Tommy Turnbull doing this work (and he could supply the barrels, too). His address was Creekside Gun Shop, Main St. Box 100, Bloomfield, NY 14469. The phone number that I have for him is 716-657-6131. I'm using the past tense because the last correspondence I had with Tommy was in 1996. He was then the premier gunsmith for Model 37 work, however.
Good luck with the old Ithaca. They are really fine guns.
May 8, 2002, 12:48 PM
Thanks. My smith is taking a look at it presently. He seems to think that he can make it fly with no receiver modification whatsoever. As he says "well, I prefer to bugger around with the less expensive part anyways." :D
If he has any difficulty, I'll contact Mr. turnbull. Actually, I already have...he had an advert for 16g barrels, but was sold out.
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