SXS's are heavy, it's what gives them that nice smooth swing and follow thru.
What? Most SxSs I've handled are LIGHT and more importantly muzzle light, balance between the hands. That makes 'em quick to the shoulder for flushing game. Depends on the gun, I guess, and I've never handled a really high end side by side. I'm one of those guys the 311 was built for. LOL I picked up a 10 gauge side by side a goose guide I was hunting with hand, once, and WOW, that thing was about 12 lbs. But, consider its function and use. It was a GOOSE gun and a 10 gauge for Christ's sake. But, normally, the SxSs are NOT smooth of swing.
With a SxS, I do note that most are less than muzzle heavy compared to repeaters or lng barreled O/Us, so more attention must be paid to keeping the swing going. Little inertia there to do the job for us.
Exactly and this is the down side of the "between the hands" balance, requires a lot of concentration to swing the gun smoothly, at least when you're getting used to it. I've found in the duck marsh that hunting with a pump one day and going out with a side by side the next can really mess you up if you don't realize this. This is how I learned this particular fact about side by sides. "Dangit, I used to hit everything I shot at with this damned thing. What's wrong with it?" LOL
This might be the reason the guy thought it was hard to shoot a side by side, don't know. To me, if I just concentrate on swing and smooth follow through, I can switch guns now without a lot of heartache. I've become a better shotgunner (which ain't sayin' a whole lot) understanding such things as this. Helps to THINK about what you are doing sometimes. I have this little 20 gauge Spartan now with 20" barrels for dove and have used it on teal. I knew going in with this thing I was going to have a real shock for balance and would have to concentrate right off on swing. I was a little concerned it might not be too good on birds for its extreme rearward balance, but I adapted to it last season and shot it very well, actually. I'd prefer a 28" gun, but it wouldn't fit in the saddle bags of my GoldWing with 28" barrels. That was the whole purpose of buying it, otherwise I HAD a 28" side by side already in 12 gauge.