Alas Ed you are quite wrong again I have seen many "factory loaded shells" With number 6 that didn't pattern worth a darn. Pattern density is the key to cleanly harvesting any type of winged creature, pheasents included. I hunt over some excellent English Setters, and most shot are close, to answer the question, I would say I need more info. Are you chasing them alone on foot, with a pointing dog, perhaps a flusher? All situations tend to differ slightly but to give a general answer for a general question, I would pick a HIGH QUALITY shell stoked with good magnum grade (nickel is a plus) shot of 5, 6, or even 7.5 with an average velocity range of 1250. Shoot a 1/4 choke and take smart shots. 50 yard wild flushes are not high percentage shots, while completing one is impressive, wounding/crippling 5 birds for every one you kill is simply not sound sportsmanship. I like personally for my situation, a home rolled concoction that chronographs right around 1200 FPS, 1 1/16 oz. of english 6's (12 ga.) for the 16 it's the same only shot charge is 15/16 oz. I have had exceptional success in my hunting situations with these loads.