Marc, I've never hunted pheasants with a 12 ga. Most of the pheasant hunting I have done has been on pen raised birds and I have shot hundreds of pheasants using a 28 ga with 7 1/2', 8's, and 9's. These were all over a pointing dog, all shots no longer than 25 -30 yards. Every once in a while because of angle I would get a crippled bird but not lost because of the dogs. Have shot wild pheasants in South Dakota using a 20 ga with reloads in #6, and #7 1/2's. A little different scenario there, many, many birds, getting up all over, longer shots. Went and bought some 3" shells in #6, because we couldn't find 2 3/4" # 5, or #6's in a heavier load. The 3" shells did the trick, and in the shooting didn't notice the recoil much in my 6 lb.4 oz. 20 ga 626E. That was the last time I used them and still have some left.
For grouse, have only killed a few, because of area, but used a 20 ga. with 7/8 oz of 71/2"s or #8's.
In my opinion a 12 ga. with 1 oz of #5, or #6's in a low pressure load would do over pointing or close flushing dogs for wild pheasants. Later in the season as birds are more warey, you might have to break out the heavier artillary. As for the grouse 7/8 oz with #71/2's would be fine in a low pressure load.
