Ah, the proverbial "Pheasant Load" thread! Seems like every outdoors BBS that has anything to do with upland hunting will have one of these threads, or a recurrence of one, on an annual basis. Unfortunately, no one ever get's it right. Our season here on Long Island has been opened since Nov 1. I've been out 5 times and have personally killed 11 birds, with a similar number killed by my companions. I have a lot of guns that can be considered upland guns that will perform well on pheasant. But this year I've been using my 1927 Parker 16ga choked Cyl/IC. I've been shooting 1 ounce of #6 lead at 1200fps and of the 11 birds killed, only one was brought to hand with its head up.
But, our hunting is done in eastern pine barren cover on state released birds. And we shoot over pointing dogs, so the shots are relatively close. We can get by with Remington Sportsman's loads, no problem. I could easily drop down to #7 1/2s, too, under these conditions. In fact, in the past, I've been successful with a 28ga and 3/4oz of #6s. I've also used 12s and 20s with their standard loads (1 1/8oz in the 12, 7/8 in the 20, etc.), and never had any issues on these birds.
But, and this is important, the few times I've shot over a flushing dog, I wanted more choke and at least a full ounce of shot. The #6s still worked fine. So, I guess you could say that inside of 40 yards, an ounce of #6s at 1200fps work well.
But, what if your conditions are not like mine? Out on the high plains, that 1200fps load of 6s will, for the most part, be like shooting blanks. Most guys out there opt for at least 1 1/4oz of very hard, plated #4s at 1300fps or better. Their wild birds are a bit tougher, have better survival skills and know every inch of the terrain. Throw in that prairie wind and you can see the need for lots of heavy shot and a good bit more choke than is required here in the east.
The bottom line is that you need to factor in the conditions as well as considering the target, when making a shell selection.
I feel slightly sorry for a man who has never patterned his gun, who has no idea how far his chosen load will retain killing penetration. But I'm extremely sorry for the ducks he shoots at beyond the killing range of his gun and load - Bob Brister