NWOBHM (Iron Maiden, Judas Priest’s later 1970s–80s albums) sets palm-muted gallop and twin-lead harmony on UK metal charts and US import racks. Motörhead’s tempo and volume sit next door without the same twin-guitar grammar.
Bay Area thrash—Metallica’s Kill ’Em All / Ride the Lightning (1983–84), Slayer’s Reign in Blood (1986)—pushes downpicking speed and shorter song forms onto independent then major labels. Megadeth and others widen the same circuit.
Late decade, Guns N’ Roses (Appetite for Destruction, 1987) and Van Halen’s hard-rock hits hold MTV and US album charts before grunge takes modern-rock radio. Pantera’s early-1990s groove metal arrives at the edge of this window.
Sound Palm-muted gallop riffs, thrash downpicking, twin-lead harmony, drop-tuned groove later in the decade, shred solos on hard-rock radio