I'd guess somewhere between 8 and 15%..lets go with 12.6%. And 100% those would disagree on what specifically makes something hardcore or metal. I read on the other thread that PiT mentions GWAR as a metal band (which they certainly are), but they certainly fill some...many of the criteria of hardcore/punk. Especially the first 2 or 3 albums (the only ones I'm familiar with).
The genres share a lot of aspects, obviously, and really, all the cool kids should all get together to bash hippies, preppies and art fags.
There was a great deal of overlap between metal & hardcore throughout the 80s. The main reason there isn't as much of it today is that metal has been successful in incorporating the language of aggression into itself, albeit in a very different fashion from traditional hardcore.
20%
It's silly. For instance, Iron Maiden is metal in it's finest form, but a band like Avenged Sevenfold or Trivium is hardcore.
Uh no, those bands are metal too.
Yeah, I've never heard of either of those bands being called hardcore. I've always known both of them as metal.
Amon Amarth recorded a song with a
cello interlude courtesy of Apocalyptica. Not to mention
power metal &
black metal bands with symphonic elements in many of their songs. Granted none of those examples endure throughout the entire song, but there are many metal bands that go beyond the traditional metal instruments.