Hi BlackTalon,
Have a mdl 37 "Riot" SN 371562XXX. Not marked police or anything like that. Has the 20" barrel, full length 7rd mag tube, parkerized finish, satin wood with checkering, plain receiver (no engraving) and flip up rifle sights. Barrel is marked Featherweight and Cyl. Can you tell me when it was made and any other info on it???
Thanks.
Your gun was made in 1976. M37's never came with "flip up" sights. The correct barrel for a non-engraved" receiver would be one with the plain M&P brass bead on it. Just a day or two ago, I saw one for sale (on Gunbroker, IIRC) that sounds exactly like yours. It had an aftermarket ramp front sight and a Williams-type folding rear sight on it.
While I'm at it, I'll answer your PM questions here too:
The barrel if a 20" model with iron flip up sights and is marked cylinder bore. After I gave the barrel a good scrubbing with bore cleaner and a brass brush I shined a light down it and noticed that the last 2-3 inches towards the muzzle have what look to be some rough machining marks (not "rough" that you can feel, but you can see the cylindrical maching marks compared to the mirror finish of the rest of the bore). Is this perhaps where they machined the barrel to the "cyl" choke at the factory?? I did notice that the rest of the bore also has similar machine looking markings, but they appear much lighter.
"Cyl" bore is just that, a straight tube that is the same diameter all the way from the end of the forcing cone to the muzzle. There shouldn't be
any marking on it at all. Is the bbl marked "Cyl"on the left side right ahead of the receiver?
I've not seen a shotgun barrel before with these type of markings and was curious if this was somehow a result of the "roto forging"??
No, the Roto-forged bbls are very smooth inside.
The bore does have some minor scratching, but not bad for a 30+yr old gun, and not pitting or rust. One other odd thing I noticed though is about 5-6 inches from the muzzle you can see a small (maybe 1/4") imperfection in the mirror finish. Its hard to describe, but it almost looks like a very slightly raised pock mark. I ran a cleaning rod over it and you can ever so lightly feel it with the rod as it passes over the area. There is no dent or bulge in the barrel, so I wonder if this again was just a defect during machining??
Sure sounds like a dent to me. The way these bbls are made, there's no way to end up with any sort of "bubble" in the wall.
Finally, are the newer barrels marked 2-3/4" or 3" interchangeable with my gun?? I know my gun is 2-3/4" only, but I have to be honest and say I don't know if that is determined by the barrel or the receiver? I came across a ported turkey barrel that I would like to install if it will fit?
Yes, any of the post 855,000 bbls marked 2-3/4" or 3" will fit your gun, but you can not shoot 3" shells as your gun will not feed/eject them correctly. One caveat though. You say you have a 7-shot gun, which means that your bbl lug will be positioned right up near the muzzle of the barrel. Standard M37 4-shot bbls will not fit on your gun because the bbl lug will be in the wrong place. If your gun is a 7 shot, you can only use other 7 shot bbls as replacements, which seriously limits your selection, as the vast majority on them will be LE 20" bbls.