My theory: The tradiditional double trigger arrangement WAS designed to shoot the back trigger first, remember the gun was designed in England for driven shooting in which one usually shoots the tighter barrel first just as we do when hunting dove over a tank.
I also think that the LEFT barrel recoils less. I have no idea why.
I've seen that theory proposed before, but I don't think it holds water. I've got an auction catalog from Christie's in London a few years back, showing something like 20 pairs of guns. There are a few with the same choke in both barrels, but most have the "standard" setup--right barrel more open than left. And pairs are obviously built for shooting driven birds. I also own a pair of Army & Navy 12's, built in 1933. Same deal--right barrel open, left barrel tighter. If you have DT's and you want to shoot the tight barrel first, absolutely no trick to go to the back trigger first.
