The 3" 16ga was indeed man'fd at least as early as sometime in the 18xx's. Some yrs back, early 1970's as best as I recall, I was at a gun dealers & a man brought in a fired empty 3" 16ga he had picked up in the woods, a "Plastic" Rem Express, no less. Operating from memory but I recall the load marked on tube was 3de-1½oz #7½. Fortunately they didn't catch on. Why ruin the perfect upland gun, when we already have the 12's??

Miller/TN
I Didn't Say Everything I Said, Yogi Berra