With shot equivalent to lead or heavier the 3" 20 can be a useful gun. This assuming it will be used mainly as an upland gun with occasional decoyed ducks where 1Ό oz of shot is plenty. A 2 3/4" 16 would be just a tad better, but not enough to really crow about.

In "MY OPINION" exceeding 3/4 oz of shot in the 28 or ½ oz in the .410 is about as useful as mammary glands on a Boar Hog. There is little doubt that 3/4 oz would be handled better by a 20 than either of the smaller bores.

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