I am ashamed to admit

that I once made the mistake of setting both set triggers on a very lightweight (UNDER 8 1/4 POUNDS ) Belgian made double in 450x3 1/4" Nitro Express. This little rifle may have been originally intended for 450x3 1/4 Nitro-for-Black loads, but was marked as a full nitro proof rifle. It was extremely accurate, and the owner had been using full nitro loads with .458 diameter bullets (although I later slugged the bores and groove diameter was less than .454"). The bores were almost pristine, as you might expect, since I doubt many shooters would make a habit of firing many full loads in this lightweight.

I was shooting from the bench, as I wanted to see just how well this rifle would group. At the pull of the front trigger the recoil of this ultra-light double, I assume, caused my finger to touch the rear trigger (although it could have been just the effect of the heavy recoil on the rear set trigger). Both shots were nearly simultaneous because both hit the target. In any case I can tell you that the only reason that I did not lose control with my rear hand as I did with my front hand was that the upward arc of the rifle was stopped by my forehead being in the way of the rear sight, rib, and barrels!!!!!! I never tried to calculate the recoil of two barrels discharging nearly simultaneously with 500 grain bullets at around 2100 fps in an 8 1/4 pound rifle, but I can assure you that it is "substantial". Moral of the story-never set the trigger on a double for the barrel that you are not shooting (if it has two set triggers).

Take the advice that was offered about using a primed empty in the second barrel to check for doubling. It is much easier on rifle and shooter than a live round in both chambers.

Jim