my experience mirrors Greg's on wild roosters. I like a bit more choke to penetrate the back of a going away bird. Crossing birds and incomers are a different story, but we do not get that many of those over my Springers compared to the going away birds.
You take me back to glorious "brass monkey" late-season pheasant hunting in Nebraska. As an ex-pat in "The People's Republic of New York State", I sure do miss those!
One thing that I learned in those days is that shot penetration on pheasants has a lot more to do with pellet energy than it does with choke. In cold weather, even #6 shot can offer marginal penetration on going-away shots due, I suspect to the effect of the cold on powders and primers and, possibly, to the ability of plastic wads to "seal". I found, originally in muzzleloading guns, that large shot traveling at low velocities (1000 f.p.s, or even less) can penetrate pheasant dorsal areas a lot more effectively than smaller shot traveling faster (nominally 1200 f.p.s. to 1330 f.p.s.). #5 shot seems to be the minimum for such loads. (According to Zutz, such loads, loaded with lead #4's, can kill geese reliably at 60 yards if the gun is properly choked.)
If it were me (And, boy do I wish that it "were"!) I would consider using Holy Black powder (Start with Ffg granulation.) to put together approximately 2 3/4 x 1 1/4 loads (for 2 1/2-inch loads) to roughly 3 x 1 1/2 loads (for 2 3/4-inch loads) using either lead #5 or #4 shot, if your hunting areas allow the use of the old-fashioned "pizened pellets". Powder and shot charges and wadding should be adjusted to achieve the best patterns. I would not be too surprised if even smaller powder charges might yield the best-quality patterns.
I would use these loads at least in your cylinder barrel but I suspect that, with time, these shells will end up in both "tubes". I think that you might be pleasantly surprised at how well such loads pattern and how well they hold up in cold weather. Great grandpaw might have had it right: Little powder, much lead; shoots far, kills dead.
Has it ever been scientifically established that one can overpet a Springer (or, does one's arm fall off first)? I miss these merry little companions, too.
