: I had the general notion that a chain-gun (or chain gun) was a biggish gun
: for which the rounds feed in on a 'chain' (belt). But from that Wikipedia
: article , it seems that the 'chain' term doesn't even refer to the belt of
: bullets. Oh well. That article badly needs a better diagram though; I
: can't see anything chain-like there. I'm wondering now where I picked up
: the term chain-gun to describe the Warthog's gun. The manual variously
: calls it a "three-barreled machine-gun" and a
: "three-barreled, electric-powered, linkless, drum-fed weapon".

I was able to find this diagram of the action for the L94A1 7.62mm chain gun, which is the secondary weapon of the UK's Challenger 2 MBT and Warrior AFV.

Unfortunately, I can't seem to find a diagram of a whole chain gun to see its insides in relation to everything else.

As for where you picked up the term "chain gun" to describe the Warthog's machine gun, like I said, this all goes back to id Software. There were literally the first people to ever refer to a Gatling-style gun as a "chain gun." Prior to Doom (or maybe Wolfenstein), nobody would have ever conflated the two. But Doom was a huge success, and the Gatling gun in the game was called a "chain gun," so the term stuck from there, and now we have entire generations of gamers who use "chain gun" to describe Gatling guns because that's just become the standard gamer name for big machine guns. It's a misnomer that's become deeply ingrained in the collective consciousness of gamers everywhere, but it's a misnomer nonetheless, just like when people refer to magazines as "clips." Every one of us is going to hear Gatling guns being referred to as "chain guns" at some point, and unless you're a gun geek, it'll probably stick in your head as the proper name from then on out. As for how id made that mistake in the first place, well, who knows how any misnomer comes about in the first place? Whoever named it probably heard the term in reference to a big friggin' machine gun (probably the M242 Bushmaster, probably the most common chain gun in use), thought it sounded cool, and, either not knowing much about guns (or simply not caring about accurate naming), called the Gatling gun in Wolfenstein and Doom a "chain gun."