Competition. 12 gauges keep getting better and lighter. I have a trim 12 gauge Benelli Montefeltro that weighs 6 ¾ pounds, which is the same or less than many 16s. It shoots everything from 7/8 ounce reloads to 3-inch steel. Why, other than for nostalgia’s sake, would I choose, say, a Sweet 16 over the Benelli? Three-inch twenty gauges, which hold slightly more steel than a 16 and weigh less, provide competition on the other side. The 16 is stuck in an ever-narrowing niche.