If the Stevens double is a modern gun in good condition you can shoot slugs in it. Some double guns may tend to "cross shoot." You'll just have to try it and see. Keep the distance short, to 30 yards or so.
NO. 3 1/2 shells are fairly new and only to be shot through rifles rated for it. If it doesn't say it on the barrel, DON'T DO IT!
Definately not. I can't think of any offhand that can, but if it is not marked on the barrel then it cannot shoot them.
If you can, it would be the newest model 311-H, and it would be stamped as such on the barrels. All the older 311 models were 2 3/4" only.
Have a gunsmith check the gun before you fire it.
Depends on the ammunition. Rifled 12 gauge slugs are accurate to about 150 yards
Most shot guns can handle deer slugs.
DO NOT ATTEMPT TO FIRE MODERN AMMUNITION until a good gunsmith checks it out.
12 gauge double barrel dual hammers on top serial #370943,how old is it,will it be safe to shoot
what do you normally shoot out of it
as long as there are no cracks in the barrel, yes. it simply means not to shoot slugs thru the barrel.
With double triggers YES
About $100 or so. The damascus/twist steel barrels are generally considered unsafe to shoot with modern ammunition.