THE old dogs of heavy metal are using some very new strategies to release their latest CDs.

“Black Ice,” the first studio album in eight years from Aussie chord-crunchers AC/DC, arrives Oct. 20. Rather than making the album widely available, the release will only be carried at two outlets: Wal-Mart and Sam’s Club.

AC/DC was likely inspired by the Eagles, who released their 2007 comeback album, “Long Road Out of Eden,” exclusively through Wal-Mart. It hit No. 1 on three Billboard charts and sold more than 7 million copies.

Never a band to mess with a winning formula, the first single, “Rock ‘N Roll Train,” sounds as familiar as ever.

Thrash gods Metallica, meanwhile, just released their latest, the Rick Rubin-produced “Death Magnetic,” which returns the band to their fast-and-furious thrashing style of the ’80s, on Friday.

It’s an unusual move given that Tuesday has long been new-release day in the US. Seeking a unified worldwide street date, Metallica’s label chose Friday to match Europe’s trend toward Friday releases.

But release dates don’t count for much if retailers won’t cooperate. After a few UK record stores started selling the album early, the band’s British label gave permission to others to sell the album on Wednesday.

METALLICA

“Death Magnetic”

(Out now)

AC/DC

“Black Ice”

(Oct. 20)