most often a firearm's barrel will be made with high quality steel. In some special cases the barrel will be chrome lined or will be made with stainless steel. both of which are used to prevent corrosion, expand the life of the firearm's barrel and to make cleaning easier.
Sharp metal object and or a gun.
NO don't eat gun metal don't eat any kind of metal
lead
Gun metal is a name for a variety of copper alloys, usually bronze, but can include brass. The Victorian confused the 2 types so this makes it difficult to know the true mixes used.
Contact the maker for correct instructions
SteelSteel
Depends on the maker. Some gun barrels are the finest quality type 4140 chrome moly or 416 stainless steel with button rifling. Hi-Point pistol frames are made from a high-impact polymer and barrels are from an alloy stainless steel.
Dozens of countries
The first were made from bamboo, which is a type of grass.
The original Gatling gun had six to ten barrels which rotated and fired independently. This was one of the earliest machine guns made.
The same thread pattern as a Belgium made Browning. Same gun, same specs, different metal in the barrels.
Watertable, forearm metal, and barrels
I'm not sure exactly what you're asking here. Generally a shotgun with Damascus barrels (those showing a spiral pattern on the outside, since they were made from spiralling layers of metal) will have been made for black powder only. In their time, fine Damascus barrels were considered a superior option, but caution should be exercised shooting such guns now, and definitely only black powder should be used. If in doubt, get the gun checked by a qualified gunsmith.
Lead, sometimes with a jacket of a copper alloy.
The very first ones were made with bamboo. ********** Later barrels were cast of brass and bronze. Iron barrels were made by heating and twisting strips of iron or steel, reheating, twisting around a rod, reheating, and hammer welding.
No. Cast iron is brittle, and shatters like glass.
Gatling gun