Rail allows you to attach accessories.
Size.
Mainly in the stock
bronze and gun metal
Stock dimensions and sights
One barrel
A person can buy a used Beretta 84 gun frame through websites like Gunbroker or at local gun shops. The frame is the main component of the gun where other parts are attached.
A sub-machine gun fires pistol cartridges. A machine gun fires rifle rounds.
You will have to be more specific. Long gun or hand gun?
There is no difference in that either can be used for the other job. Of course there are hundreds of types of guns around in the building industry.
Serial numbers are required by law to be on the frame (aka receiver) On the Beretta 92, they are located on the left side of the frame, about halfway between the trigger and muzzle. Other models may have them in different locations, but always on the frame. PS- by law, the frame IS the gun- everything else is a part that CAN be replaced, but the receiver IS the gun.
The Minigun is Gatling gun where the barrels are powered by an electric motor. The Gatling gun, was a hand cranked, multi-barreled gun.
none.