While traipsing through the wire grass at Morrison Pines I picked up an empty shell, it was a 3 inch 20 with 1 1/4oz of #4

I haven't used anything bigger than a 20 for quail. Admittedly I take the Purdey light game gun but the 2 inch RST are equivalent to a 28 or 20 with 3/4 oz loads. I also enjoy the 410 but it is a Fox double no repeaters:nono:

If were going to count 16's as quail guns I'll post a couple. :rolleyes:

If you're talking pen raised birds, a 20 gauge is the max. Wild birds are a little different story. And when I'm running the dogs off horse back then it's usually my 16 gauge NID, primarily because she's a bit of beater and the scabbard will pretty quickly ware the bluing off the barrels.

A 16ga quail gun. AH Fox A grade, factory straight grip, 26 inch barrels choked IC/M. In all honesty I'm considering some 16's for quail and will look into a flat of RST 2 1/2 shells and a 3/4 oz of shot. Should make for a great woodcock load as well.

That sure looks like a fine quail gun to me!

Here's one for you Mills. A sweet little VH 20 with 26" cyl/M barrels weighing an even 6 pounds. A great cofiguration for Quail.
Also shown with its little step-sister a VHE 20, quite used and abused.

And just so Dr. Bob doesnt get lonely, a Lefever Durstan Special 20 ga.
with ejectors, 26' IC/M weighing under 6 lbs.

Both look good

That Lefever is nice too

My quail guns in the field at Pine Hill Plantation
 

VHE 20 and Webley & Scott 28 do the trick. Apologize for the photo orientation.