SXS's are my favorites, but any shotgun will do. Last year I got birds with:
PUMPS:
Winchester 1897 16 ga.
Winchester 1897 12 ga.
SXS:
Savage Fox B 12 ga.
Lefever G 12 guage (2 1/2" black powder)
Sauer & Sohn 12 ga. (pre-war)
OTHER:
N.E.F. Pardner 20 ga. single
There were a couple of other shotguns I used, but I can't remember which ones.
For sharptail, I always use 5-shot in the tight-choked barrel and 6 in the more open barrel (or 5 for the first shot and 6 for the second - in the case of pumps or others).
For ruffies, I prefer 7 1/2 and then 6-shot, in that order. With the heavier loads and larger shot sizes for sharptail, I tend to lean towards the 12 gauge and heavier guns. For the ruffies, I like slightly shorter barrels, smaller gauges, and lighter guns overall.
This year I'll have a couple of new 20 gauge SXS's to play with. I have a feeling they'll become my favorites.
SS