Various metals. Steel, polymer, or a combination of both is pretty common. Some really cheap guns are made from some sort of zinc or other cheap metals.
No.
Rifles, shotguns, handguns
Handguns and long guns.
Italy
Italy and USA
Yes, they are.
trainers are made from leather and silk
copper and silver
Wood
Rifles, shotguns, handguns, machine guns.
Rifles, shotguns, handguns, machine guns.
If you're asking when were handguns first made, the answer is the 1400s. The first handguns were basically small hand-cannons.