Being that I use 12 gauge exclusively...some thoughts:
First and foremost...no matter what manufacturer brand or shot size,
always pattern it through
your shotgun...
The most popular shot sizes among pheasant hunters are #6 and #7 1/2. I've used #5 with great success, especially on the tougher pheasant. But if all the dope and data on what it takes to consistently kill pheasants stone dead from all angles and at various distances were fed into a computer, the machine would likely choose #6 shot with #5 in a very close second place.
Smaller shot sizes work okay at closer ranges, but they lack the ability to break heavy bones and penetrate to the vitals of a bird at longer distances. #4 shot is great if
enough choke is used to keep pattern core density high, but I’d really rather have #5 or #6 and less choke.
When choosing between the two I prefer to go with #5's so long as the shot charge weighs no less than 1 1/4 ounces, but I always choose #6 when using lighter shot charges in order to keep pattern density high.
As far as the smaller birds like Chukar and Quail...I would go with #7 1/2...even #8 when flushing them in close...as usually happens.
There are those who will use no choke other than Full when hunting pheasant, but most hunters are better off with more open chokes. Improved Cylinder is probably as close as we’ll ever get to ideal for pumps and autoloaders. And if a better combination than Improved Cylinder and Modified ever becomes available for double-barrel guns, I’ll be the first to stand in line.
It must be mention that the use of nontoxic shot is now required in some areas of the country regardless of the game being hunted. Hunters who go after pheasant and other game birds in those areas can no longer use lead shot, which is the same as it has been for waterfowl for several years now. Steel shot works okay on pheasant so long as pellet diameter is a couple sizes larger than lead.
For example, those who prefer #6 lead shot would go with #4 steel while fans of #4 lead shot would opt for #2 steel. When using nontoxic shot such as Tungsten-Polymer, Tungsten-Matrix, and Bismuth, use the same-size shot as lead since all have similar densities.
Those types of shot are actually superior to steel. While considerably more expensive, a good wing shot isn’t likely to spend a fortune on shells with today’s daily game bag limits on pheasant being what they are. Actually, anyone who desires to use an older gun built prior to the steel shot days has no choice but to use one of the other nontoxic options.