While readily that in this current age 16 gauge shells are harder to come by.
"Both" of the other Axioms are of course incorrect. For instance I have one 12 ga gun which is lighter than a couple of 16's I currently own & also lighter than a few 20's I have previously owned. I Could never see carrying around a 7 lb
20ga so those took the walk. If I'm going to carry around 7 lbs of gun it may as well be a 12. "Kick" is of course a result of the weight of the gun & the load used. Any of these gauges if the heaviest available load is fired from the lightest weight gun of the gauge can have a pretty vicious kick, while if a more moderate load is fired from a gun of slightly more weight then the kick comes under control. The old 2 3/4DE with 1 1/8 oz of shot is rather comfortable from any 16 of at least 6 lbs weight for most hunting situations. The 2½ DE-1 oz is even more so, no viciousness at all there.
Of course if you insist on stuffing a 1¼ "Mag" load in a sub 6lb gun doesn't matter if its a standard 16 or 3" 20 it'll Kick the Snot out of Ya, more so than a 1¼ oz load from a 7lb 12.
One axiom you can bank on is the bigger the hole down the barrel the more shot it is capable of efficiently handling & also the gun will need to be heavier to handle the more shot.
