At least half the industrialized nations in the world have built machineguns. Please refine your question, and repost- we'll try to get you an answer, but right now your question is too broad to give an answer with any real meaning. Sorry-
By your mommy
A lot
machine guns
No. Machine guns will beat Gatling guns.
Machine guns.
Yes, machine guns are better than Gatling guns because they fire more bullets faster than Gatling guns. Gatling guns need to have bullets and have to be hand cranked at the same time but machine guns does not need to be hand cranked. Machine guns only need bullets.
Rifles, shotguns, handguns, machine guns. Mainly rifles and shotguns.
They are still made, and are made like any other firearm- by machining metal parts.
Yes, machine guns were used in WW2.
Yes. There were machine guns in WW1. There were Gatlin Guns, a type of machine gun, in the Civil War.Yes
Machine guns didn't cause wars.
Some machine guns are and some are not. The answer would be yes and no.