Guns N' Roses Appetite for Destruction is Heavy Metal
Now we've got some 70's metal albums properly tagged, and even though there isn't much of that I'd like to raise an easy one to compare to Appetite for Destruction in terms of heaviness: Taken By Force. On the whole, Taken By Force is heavy enough to consider. Not every Scorps album is heavy metal, but a few of them fit the bill, but this is probably one of their lighter "metal" albums due to having come out at that time, but because metal was a little lighter on a regular basis at the time, this does count. I don't see any reason an 80's album shouldn't count. If we can include that, as well as some of the 80's Priest catalogue, then I know for certain that the debut album of GNR counts. About every other song is loud, heavy and builds itself on metal spirit and aggression. And no, I'm not talking about "hair metal," which isn't even real metal.
The comparisons are simple. Welcome to the Jungle, It's So Easy, My Michelle and You're Crazy (practically a Motorhead song in a few ways), are very metal in both composition and spirit, Paradise City and Anything Goes kinda switch between hard rock and heavy metal, and even lesser metal and more hard rock like Out Ta Get Me, Think About You and Nighttrain are heavier than bands like AC/DC and shouldn't even be considered for the same league of heaviness. Basically, the album is built on metal spirit, and it does get difficult to really draw a line where the difference between hard rock and heavy metal truly lies. But I've heard plenty of albums that carefully bridge that line, like many of us here must have as well, and can we really say that Appetite for Destruction doesn't have an edge on those other albums due to pure metal spirit and production?
Guns 'n' Roses certainly have a heavy sound in comparison to most other rock music (as well as some of the lighter heavy metal releases to be fair) but the instrumental techniques utilized are still drawn from rock rather than metal in my opinion (i.e. a bluesy feel, open-string riffs, pentatonic licks, 4x4 rock beats, no use of double-kick, minimal use of palm-muted down-strokes, a groovier edge to their riffs & rhythms that has you tapping your foot rather than banging your head, etc.). Scorpions have a few metal tracks here & there but for the most part sit much more comfortably under the hard rock tag too in my experience (which amounts to their run of six albums from 1976 through to 1984). The only Scorpions album I've heard that's worthy of a metal tag is "Blackout" which, to my ears at least, contains a mixture of hard rock & heavy metal songs.
Let's see what others think though as I've just posted this nomination in the Hall of Judgement.