What is the value of a model 12 16 gauge with a 26 inch cylinder choke plain barrel? According to the seller the gun was manufactured in 1923. Gun appears to be in decent original condition - well used but not abused. Seller also indicates that the chambers are 2 and 9/16. Could the gun be converted to 2 3/4? If so what is the cost?

I'll take a shot. If by "decent shap" you mean normal wear on a 80+ year old Field Grade gun with plain barrel/ 26" no choke(cut?). I say around here aprox. $350-$375. Chamber could be lengthened safely, but measurement of wall should be made.

NU-LINE GUNS in Mo. re-did my 1917 nichol steel Mod.12 16ga with two barrel and slide assemblies including chamber sleeving and opening the ejection port to accomadate 2 3/4 shells and reblued all the metal surfaces for about $600 a few years ago. Google Nu-Line and I'm sure you'll find them. They did beautiful work, but I'm not sure the result is worth any more than what the original gun was worth though. At least my gun is useable with regular shells now...Geo

The good news is you can buy a lot of 2 1/2" 16 gauge ammunition for $600 today. The bad news is a lot of individuals seem to think having a short chamber must add $500 to the price of the gun, at least from the prices I've seen.
Every now and again, a guy gets lucky, and one of the older 2 1/2 guns will happily digest 2 3/4 ammunition like it was designed to do that. I just watched as a first year 20 gauge I used to own was put through it's paces at my club patterning board, and without a hicup, it digested every brand and load we could stuff in the chamber, which, along with the ejection port, were exactly as they left the factory, back in 1913. Nice patterns, too. I mentioned something about low pressure loads, of the correct length, and got laughed at.
Best,
Ted

PS Ben-T, if it is the gun I'm thinking it is, it is an actual CYL marked barrel, not cut.

For whatever my opinion might be worth to you, I'd leave it with the short chambers and buy short lower pressure shells. They are a lot more available now than they were when I had mine redone. I wouldn't shoot steel in it though, even if it is cylinder bored...Geo

Wright Gun Shop in Illinois does this for $95. He specializes in model 12s.

Come to think of it, there were a few other repairs done by Nu-Line in addition to the chamber sleeving. Seems like the gun and both front ends had to be practically rebuilt. I don't really remember what the chamber lengthening cost, but I remember the total. It is a gun that is dear to me, so the expenses seemed justified...Geo

DON'T convert it! use the 2 1/2" shells. Converting cost more(even at $95) than it's worth and ruins the historic value of the gun. Leave it as is. It was designed for short shells, use them.

You might find that it handles 2-3/4" shells just fine. Some 16's do, some don't. Try a few brands. Pressure is not an issue with these guns.