poprivit:
Modern doubles such as Chapuis, Kriegoff, and probably Merkel are regulated by firing the front-trigger/right-barrel first, then the remaining barrel a few seconds later. For a scoped medium-bore double in particular (ie 9.3x74) this can be critical.

The British and European standard is front-trigger/right-barrel first, but on vintage guns with worn first-barrels (from plenty of one-shot kills, ...or misses!) it is common to have a gunsmith reverse the triggers to even-up the wear and ultimately maintain regulation.

...and BTW, we poor owners of double rifles shoot 'em pretty-much the same as the rich guys!