I have been reading all I can find on the 2 bores (and I have not been able to find much either) but all I can find to read agree that "only" 275 to 325 grains is about right. You see, more than that makes the recoil beyond realistic for any man to shoot, as far as what I can tell.

I was suprized that in all the writings I have found, they say the 2 bores use less powder than the 4 bores do.
I guess with 3500 grains of lead, more powder is not necessary, and in fact, it's dangerous to produce that much recoil.

If I were going to shoot it, the load I would start with is about twenty grains. I would work up one grain per year, until I died at the age of 100 years old ------- and the gun would never kick me bad at all.