If your looking to shoot birds, id say the 20 gauge, puts a lot more lead in the air. a 410 can be downright discouraging. You'll also notice with that single 20 kicks as hard as a 12. sweet gun though.
My .02 Ameros in this arena is still the Savage 24 combo 22LR/20GA.
IMHO, it is a VERY formidable small game-getter supreme
If the "single-shot" variety is not objectionable, and in this case what you are actually looking for, then that takes the major disadvantage out of the equation.
The only other possible disadvantage that I can think of is the weight. Which is bad on one hand, due to obvious carry issues, but good on the other hand, as it helps to keep the recoil at a minimum when shooting the shotgun barrel.
All Model 24's break down into easily managed pieces for mobile packing if desired, with the 24C being specifically designed to be packed in it's own "roll pack" only 20" long.
I have been doing some experimenting with my Model 24S-E and a Bushnell Trophy "red-dot" sight. What I have found is this:
Because the Bushnell Trophy has 4 different selectable reticles and is not "ultra-precision," I would get a slight variation in grouping (when using the .22 barrel) when switching to the various reticles. In other words, I get it sighted in with the smallest MOA reticle, and it would be off slightly if I used a different one (not touching the settings).
Similarly, due to the dual barrels on the gun, if I sight it in with one reticle using the .22 barrel, there is a slight variation when I use the same reticle but shoot the 20ga. barrel.
Amazingly, the two slight inconsistencies lead to a combination where one reticle is "dead on" with the rifle barrel and "really, really close" with a slug in the shotty barrel.
Now, I'm not a precision shooter, but with this combination, there isn't any small game critter (and some not-so-small) that's gonna like it out about 40 yard or so, and squirrels and-the-like out further (.22). :
i really dont recamend a 410. the ammo is to pricy and u reall dont get any exitment from it. i have a remigtom 20 ga and it works perfect for squirrl or dove hunting. im gonna get a rem 7mm rem mag its awsome!!!!!!