I’ve got a variety of 20 & 28 gauges as well as .410’s that we use for ducks & geese as well as upland birds. With the high quality ammunition we now have access to, you might be surprised at what you can do with sub-gauge guns. Here is what I have experience with, as well as some suggestions based on my experience with them…
20 gauges - Beretta A-400 as well as Winchester SX3’s, CZ over/under. I’ve found the best, most reliable to be the SX3’s and that’s what I recommend if you can find one. They’re better than the current SX4. I’ve had a fair amount of trouble with the Beretta, which I’ll elaborate more on later.
28 gauges - Beretta A-400’s, Mossberg O/U, Ruger red label O/U, Remington 870. Again, problems with the A-400’s, but I love them.
.410’s - Mossberg O/U, Pointer semi-auto and Remington 870. The Pointer (Turkish made) is a surprisingly good little gun. With TSS shells, you’d be amazed at how effective it is on Greater Canada Geese. Another good option in a .410 auto is the TRI-Star.
Beretta sub-gauge problems - Beretta has a big problem with their sub-guage A-400’s. Simply put, they don’t function reliably without having some work done on them. Cole’s Guns is the USA warranty station for Beretta and they have 3 levels of service they’ll do on your 20 or 28 guage A-400 to get it working like Beretta has a great reputation for, but it’s not covered by warranty. All in, it runs about $450 plus shipping to/from their location. They’re wonderful, well balanced guns that point like a dream. I love them, just wish they’d go bang every time without being fussy about feeding.
If I was buying a sub gauge gun today, I’d try to find a Winchester SX3. Mine have been utterly reliable, they point well and I wish I had some in other gauges besides just 20.
.410 Honkers