Remember: you don't hit the bird with the bore. You hit it with pellets. #4 from a 20 Gauge hits EXACTLY as hard as #4 from a 12, because they're the same pellets.
much prefer my light little Itheca/SKB 20 ga double anymore.
My old Ithaca/SKB 20 Gauge O/U is a personal favorite. Just bagged a pheasant Thursday night with it, in fact. It was a relatively long shot, through a bush, and it still dropped like a stone when I hit it (with the
second barrel
).
The 12 Gauge is not necessary for
any upland bird. You can buy yourself a bit more leeway at long ranges, by using a heavier payload and a more open choke, vs. a 20. That's about it. It's usually not that easy to hit anything at long range, because birds don't move as predictably as clays.
If you find a 12 that you like, get it. The Beretta 686/687 O/Us are only about 7 lbs. in 12 Gauge/28", for example. That's not too heavy. But, if you shoulder a 20 and you like it, get that. There's no reason not to.
I use a mix of 12, 16 and 20 semiauto, SxS and O/U guns, depending on what I feel like that day, and the weather (snow and plastic go together a lot better than snow and nice walnut
). I can't recall any time when would have bagged a bird with the 12, but with the 20 I couldn't. What really matters is gun handling, and that can be unpredictable. Sometimes, a quick gun is the ticket; sometimes, a trap-like swing works best. So a heavier, longer gun might work best, or it might not, on any given day.