Shotguns fire shot shells. Handguns can fire specially made shotshells.
Yes.
Do not attempt to do this. You may cause damage or injury.
In general, no. Unless the gun is marked for 3 inch (or even 3 1/2 inch) shells, you should not attempt to fire 3 inch Magnum shells, even if they seem to fit. However, if you have a gun made for 2 3/4 inch shells, and have 2 3/4 inch "magnum" shells, IF your gun is safe to shoot, it should be safe to shoot those "baby" magnums.
Yes it will as well as 22 short and long rifle, but the rifle will only shoot the 22 LR shells as a Semi auto and the shorts and longs you will have to manually cycle the gun by hand
You could eaither shoot dove with a 20 gauge shotgun or a 12 gauge shotgun. You should also use a bird shot shells
A 12 gauge shotgun cannot fire 20 gauge shells.
Yes. A 3-1/2" chamber will accept 2-3/4" & 3" & 3-1/2 shells
No
Knife is to Stab, as Gun is to Shoot.
Yes, you can shoot 2 1/2,2 3/4, and 3 inch shot gun shell in that barrel.
That would not be good, so don't try it.
It will shoot any type it is chambered for.