Just today at a doctor's office read a blurb in an outdoor magazine about a Benelli 28ga with 3" chambers. Fiocchi is loading shells in that length with 1 oz of shot. the writer said he & several others had carried these on a 3 day pheasant hunt & regularly killed pheasants at a "Verified" 60-70 yards. He didn't state the size of shot they were using. Personally I sort of took that with a "Grain of Salt"
I have shot 1Ľ oz of shot at approximately 1100 fps from a sub 6lb, by a couple of ounces, 16gauge with no ill affects. I would not want to shoot it in a high volume situation though. I currently have 5 16 gauge guns. One is a H&A single, three are doubles & one is a hammer drilling in 16x16x9.3-72R. The sub 6 lp'er is a Halifax by Darne with double proof, the double are a Baker Black Beauty & an H grade Lefever Arms Co. The drilling is a Miller & Val Greiss. I see nothing at all wrong with a good 16 but have little time for anything smaller than a 20.
Never saw anything out of either the 28 or .410 which would not be expected of them. Fact is it is not hard at all to have a 30 yd gun, but every 5 yards you add keeps taking More & More & MORE.