Modification question, would it be right
 

A question about what to do. An early 1900s classic English SxS 16ga in very nice overall condition. Not a London Best Gun. Barrels are 30" and do not appear to have been cut. Chambers are 2 1/2" and chokes measure a cyl/cyl. I cannot confirm original specs as to factory chokes, but I question the cyl/cyl.
As 16ga 2 1/2" shells are pure unobtainium and probably will be for the foreseeable future would you look to having a good smith lengthen the chambers to 2 3/4"? I currently load low pressure 16s in that length for a 1912 J.P. Sauer that had its chambers done at some point it its life. I do not like altering a gun but I hate to see a solid, well preserved gun become a display piece b/c ammo is not available. TIA

Why not reload for the new gun?

Those chokes may very well be original . My 12 ga WW Greener has 30" cyl/cyl as does my Scottish 20 ga with 30" cyl/cy/.
Are those fluid steel or damascus barrels?
Hopefully someone with more mettalurgical knowledge will weigh in. The English had no problems altering guns to fit their needs. My first Parker a 1 frame VH 16 had its chambers lengthened back in the 1980's.
I have 11 16 ga's, most with short chambers so I've loaded short 16's for years.

I would not do anything to alter the barrels, ever, especially barrels belonging to an English gun. It’s hard to find English guns that haven’t been messed with. Brits know how to take care of their guns and refinishing didn’t effect the value like it does with American guns, but any alteration of the barrels will reduce the value of a British gun.

Lengthening chambers will let you shoot 2-3/4” ammo, but at some point low pressure 2-1/2” shells will be available, but your barrels will still have been modified.

I agree and concur with what's been offered in response to your question. IF the gun is still in proof, opening the chambers will take the gun out of proof, and, as stated already, reduce its value. Also, the Brits removed lots of metal in making great handling guns and it is not uncommon to have barrel walls be in proof and be much thinner than what you might find in an American gun of the same vintage. Opening chambers and, especially, forcing cones, could be disastrous.

Good things come to he who waits.

For your consideration, I've used 2 3/4" low pressure reloads (1200 fps or less) in all of my English 16s for years. With absolutely no problems. And... if you reference Sherman Bell's 2006 testing in DGJ of 2 3/4 shells v. 2 1/2 hulls, you'll see virtually no to very little pressure increase due to the 1/4" more hull length. Just use the same ammo you make for your other 16s. You'll be fine.

As others have said, i would not open the chambers up.

Ken

If you measure Remington dove and quail loads you will find the unfired length is 21/4" and the fired length is 21/2". I have used them for years in short chambered damascus and fluid steel barrels with no problems. Opening the chambers will devalue your gun.

Will lengthening the chambers devalue your gun? Only to a "collector" If you sell your gun as a "Shooter" it will most likely sell quicker and you still might make some scratch on the deal. Personally, I'd rather buy a gun that will take 2 3/4" shells than a gun that can only use 2 1/2" shells. After all, we are buying and shooting "used guns". Enjoy them and shoot them. If the gun needs some work to make it usable for you then make it usable. It's a personal decision and one that only you can make.

As stated before, opening the chambers on an English gun and not reproofing it does make it out of proof and devalues it. The devaluation is not as severe on American guns because they were not subject to proof laws.