Various laws in the United States say that a fully automatic weapon is one that fires more than one shot with one pull of the trigger. Yet it occurs to me that double-barreled shotguns can fire two shots at the same time by pulling on two separate triggers simultaneously. Suppose you had a handgun or rifle set up with two triggers, but instead of side by side they were one in front of the other. As the first is pulled, the second remains stationary. When the first trigger actuates and a shot is fired, it contacts the second trigger. By continuing to pull back, the first trigger keeps moving but does nothing. The second trigger, however, in an identical but completely separate process, fires the weapon again. In effect, you have a two-round burst without a fully automatic weapon. A single, smooth pull gives a double tap.
Would this be legal, being in the same vein as a double-barreled shotgun? Or would it be different because both shots are being fired from the same action mechanism?