Bwana, you could go into a ware house full of one model and brand of the same name double rifles with consecutive serial numbers, select one and work up a perfect load for it. Then try that same load in every other one in that ware house, and I doubt that more than one out of twenty would shoot the same. They may be close, but some may be way off as well. Even if you know the factory ammo it was regulated with you are not going to know the lot number of that ammo, and it may or may not shoot as well your test target. The key IMO is when buying a new double rifle you need to obtain dies and powder and be prepared to do a little tweaking. It is a simple fact the to get the absolute best from any double rifle one must hand load! Of course the new buyer may be one of the lucky ones who gets one that shoots just about anything, but he shouldn’t count on it!

I know many guys, who shoot double rifles, and they are satisfied with the accuracy of regulation in their rifles with factory ammo, but few of them regulate properly. They simply think as long as they hit a cape buffalo someplace close to the aiming point out to 50 yds they are fine with that.

I am not fine with that type of regulation performance and I want my rifles to shoot properly so once I find a proper load I buy enough powder of the same lot number and load 100 rounds of new, sized, brass with that load and set it back for hunting. I usually have about twenty pieces of brass that I practice and stump shoot targets like wild hogs for practice and reload those twenty pieces of brass till they wear out, and buy twenty more for the same purpose. When I want to go hunting real big game, I take ammo from my 100 stash. In a big bore double rifle 100 rounds will last you several years if used only for serious hunting of dangerous game, and the other twenty stump shooting loads will do for everything else!