Keith,
The Boss patent single trigger is the most common use of a single trigger that operates on the involuntary pull.
Best,
Ted
Thanks Ted. As I said, I'm not a single trigger guy, and never owned a double shotgun with a single trigger. I've shot some that belonged to friends, but never really wanted to own one after reading about the number of problems they had compared to double triggers. However, I have read quite a bit about them over the years, and never encountered any info on a design that was said to utilize an involuntary second trigger pull to reset it for the next shot. I have read about the designs that use small inertia weights to use the recoil of the gun to reset them, and other more complicated designs.
I did a little Googling to try to learn more, but came up empty. So I'm still left wondering how some gunmaker/designer discovered the apparently universal involuntary second trigger pull, especially since ultra high speed photography was primitive at best when these triggers were designed. I'll probably screw up my next shooting session by concentrating on trying to catch myself doing it. I'm guessing it became apparent while working on or trouble-shooting some other design, and instead of trying to beat it, they decided to make use of that extra involuntary motion. Pretty ingenious, if that was how it came about.