Thanks AKM, I will chip in, hope I can help.
MikeH:
A couple of points on the stock first. Many early Brit or European doubles had a lot of drop in the stock, but it does not necessarily translate to recoil on the cheek-bone. Remember that they were built in an era when African and Indian big game hunting was a very real thing, and the large-bore rifles and bore-guns of the day were designed to be shot standing off-hand at fairly close range (by today's standards). Stocks were designed specifically for off-hand shooting in a very upright position, so the shooter was not 'crouched' into the shot, but remained in a position to respond immediately to the consequences of the shot! Vintage hunting rifles were
never intended to be fired from a bench! ...or even sitting, let alone prone!
Also, the rifles in question recoil with a 'big shove' rather than a 'belt'. With today's relatively light-weight magnums, a kick in the chops usually results from high 'recoil velocity' whereby the body's inertia prevents it being pushed back quickly, so the muzzles have to rise, and a belt in the face ensues.
Having said all that, some were stocked for tall men with 'long' faces, and may need modification. Why not try bending the stock, especially as it sounds like you have nothing to lose? I have only done shotguns in the past, one a Cashmore side-lock, but I'm about to do a Rodda crystal-indicator sidelock .500 Cordite Express with an old Indian re-stock which has incorrect cast for my build. I simply clamp the action-bar in a padded vise, build a jig out of scrap timber incorporating a furniture clamp, and set it up so that hot linseed oil can be ladled over the wrist, while putting a turn on the furniture clamp every few minutes. I can post more details if required.
Personally, I reckon the .577 x 2 3/4 is the best chambering for a double rifle, it's probably my favourite cartridge, particularly in the 'Light Nitro' loading. After being asked about it numerous times, I finally consolidated my thoughts on the cartridge and tossed a summary up on the web,
view it here! Regarding loads:
If the barrels are 26 or 28 inch, I would recommend starting at ~90 gr Varget beneath the 650gr Woodleigh RNSN (Cat.No. 5 for BP Express), with a magnum primer, and just enough felt wadding (or a BIG bunch of dacron) to slightly compress the load. Use a chrono and work up to 1650 fps or thereabouts, looking for barrel regulation. That velocity should be achieved with less than ~8 tons of pressure, well below the 10 tons generated by the original BP Express load with only a 570 gr lead bullet.
(all the usual warnings, start 10% below, no liability, etc, etc... )
If you want to shoot lead bullets, you need go no further than Sherman Bell's recommendations in the Spring 2005 DGJ. He brought a Greener hammerless double chambered for the 2 3/4 .577 Express out to Australia, and hunted buffalo with ol'mate Dave L_. He used 570 gr 'long flat nose' (LFN) lead bullets from an LBT mold, loaded over 70 gr IMR4198 with 8 gr dacron wadding, and they produced 1700 fps MV and 3 1/4 inch groups at 100 yds (with express sights). Worked well on buffalo, too!
