LOS ANGELES — Like the amped up comeback tour of two rockers who had their heyday sometime in the mid-’80s, Sylvester Stallone and director Walter Hill (“48 Hrs.,” “The Warriors”) join forces for a hard-hitting exercise in beefy, brainless fun with the New Orleans-set actioner “Bullet to the Head.”

Taking its B-grade scenario à la lettre, this assassin-cop buddy movie aims to accomplish little more than delivering tons of kinetic wham-bam fight sequences and LOL one-liners, which Stallone recites from a face that seems literally frozen in time.

Adapted by Alessandro Camon (“The Messenger”) from the French comic book series by Matz, the film shifts the setting from New York to New Orleans (tax credits, anyone?), though that location is never officially named — and, like many things in this fast and easy shoot- `em up, such details don’t really matter.

An opening assassination scene, replete with a prostitute and lots of cocaine, introduces us to Jimmy Bobo (Stallone), a tired and heavily tattooed hitman who’s seen it all but still can pack a nasty punch. When Jimmy’s partner (Jon Seda) gets sliced up by a muscle-bound meathead (Jason Momoa) with expert mercenary skills, Jimmy vows revenge. He teams with an out-of-town detective, Taylor Kwon (“Sung Kang,” “Fast Five”), who’s been sent to investigate the murder of his former partner — who turns out to be the very man Jimmy took down.

If this sounds complicated, it isn’t, and once the major plot points are dispatched with, “Bullet to the Head” dishes out 90 minutes of old-school mayhem, accompanied by plenty of comic banter between the aging thug and his Korean protege. It’s as if Stallone and Kang were swapped in for Nick Nolte and Eddie Murphy in yet another “Another 48 Hrs.,” with Bobo showing Kwon the ropes while insulting his ethnic origins to no end, even if it’s clear we’re in bromance territory from the get-go.