Being an owner/breeder/trainer/hunter/triler of Brittanys I often do a lot of what our US friends term 'upland' hunting here in Australia. That usually consists of chasing our native Stubble quail as well as rabbits, hares, & the odd released partridge & pheasant.
Unfortunately we dont have any Ruffed Grouse over here - piuty. I'd love to have a go at them as I reckon they would be the perfect upland bird.

Anyway, for years I used a lovely little Begium B25 Browning 12ga chocked open mod & tight mod (18thou bottom barrel & 24thou top). This is a really lovely gun with 1 1/16oz loads going through it's 27 1/2 inch barrels. Just a real joy to use.

However, a couple of years back I bought a nice 2nd hand Beretta 687 Silver Pigeon 20ga.
It has 30 inch mobil choke barrels. I've been using this with 1oz 10's & have found that my quail hunting has never been so good. Light to carry (both gun & shells), easy on the shoulder, & the 10's kill quail extremely well even at 40-45 yard distances with very little damage to the carcass.
It's also a great rabbit gyun with 1oz 5's & excellent for partridge with 1 1/16oz 6s.
I even use it for pheasants with 1 1/8oz of 4's or 5's with excellent success.

Based on my experience with the 20ga I wouldn't hesitate to go down to a 28ga for quail, rabbits, partridge. Would love to one day get hold of a nice 28ga SxS.
Unfortunately, over here, most 'sub 12 gauge' shotguns are either expensive quality pieces or cheap rubbish. Something like a nice Ruger, Beretta, etc would offer quality at reasonable cost.

I 'spose they will come along eventually but I hope they're not too far away.
As an aside, I did have a chance to pick up a nice 28ga Winchester 101 many years ago but just couldn't afford it back then, apart from which, at the time 28ga loads were all but non-existent in Oz. Love to get my hands on that gun now.

Bill Allen
Melbourne Australia.