If you want a double barrel shotgun, go with it. As far as what works for upland hunting, which I do plenty of including chuckar, a 12 gauge semi auto is my preferred choice. Here, for chuckar you can hunt with a full magazine and are not restricted to just three shells. Often, chuckar flush far if they are high pressure birds and the additional shot in a 12ga is helpful. Trying to kill as many birds in a flush is the key to success where I hunt as opportunities can be fleeting.
For grouse, a smaller gauge can be useful as the birds are often very close, but then again you can accomplish the same thing with a lighter 12ga shell
Chukar and pheasant hunters in E. WA use 12 ga autos on wild birds. M2 Benelli is popular. Not sure about released birds so much because I've never hunted those with any regularity. There were some WDFW release sites where we hunted on the Snake R. but those were public and the birds were all harvested the first day of the season by hoards of hunters. We usually hunted on private land with permission.
I always hunted with a 12 ga sxs because it was a good light game gun. Today a Benelli M2 would be my choice for pheasant and chukar in any situation. I haven't hunted anything in about 15 years.