Please take it easy on me fellas, I've never dabbled in shot shell reloading (only rifle and pistol cartridges). I've been interested in getting an English SxS but notice that a lot of them are nitro proofed to 3 ton per square inch and chambered for 2 1/2. I'm not overly interested in getting setup for reloading shot shells and was wondering if I could simply take some of my 2 3/4 #8 target loads and cut them down to 2 1/2, place a shot card and roll crimp them or would they probably be too hot for the gun? I doubt I'll be running a ton through it so low productivity numbers shouldn't be an issue. Short of that I suppose I'll be limited to what I can buy off the shelf. I appreciate any help, thanks!
You say you haven't reloaded shotshells so I assume that you want to know about the possibility of cutting down factory target loads. Consider this...
Your gun was proofed at 3 long tons per square inch, approximately 6600 pounds per square inch, this is the maximum load that this gun was considered safe for when new. What alterations to the barrels have taken place since then, maybe 100 years or more?
Modern target loads, although modest in velocity and payload are frequently not low pressure, 10,000-12,000 psi being quite common to reliably cycle all types of autoloaders.
To cut down and recrimp your existing 2 3/4" shells you will need to open the crimp, pour the shot out, remove the wad ( the powder will follow), shorten the hull, pour the powder back in, oops, now the wad is too long - trim the wad, pour the shot back in, then add an overshot card and roll crimp. This will shorten your shell to fit the chamber but it won't lower the pressure. And you will now have one complete cartridge. That's a lot of fiddly work for one cartridge, how much effort do you want to put into a couple of boxes of ammo?
For hunting purposes ( unless you have much better hunting than I do) and a couple of trips to the range per year factory ammo makes much mores sense. Prophet River Firearms and Ellwood Epps, both CGN sponsors carry a variety of 2 1/2" ammo made for your gun, assuming it's nitro proofed. In addition, Kent Cartridge is ( or was) the Canadian distributor for British made Gamebore ammo and any store ( except Cabelas) that sells Kent ammo should be happy to order some by the flat.
Get a good gun, feed it the ammo it was intended to use and you'll be hooked.