The Geritol action genre lumbers on in the lackluster “Bullet to the Head,” starring Sylvester Stallone, or at least a beef jerky replica. He plays Bobo, a Louisiana hit man reluctantly partnered with visiting D.C. cop Kwon (Sung Kang) because neither can trust his superiors. The film is based on a French graphic novel, although given the troubling level of gunplay and gratuitous nudity, it could have been based on the daydreams of a worrisome 13-year-old.

The film is directed by action veteran Walter Hill according to the mismatched buddy pattern established in his 1982 Eddie Murphy-Nick Nolte hit “48 Hours.” The unlikely partners swap put-downs, mostly ethnic and mostly growled by Stallone, while charging into rooms full of anonymous henchmen and creating a diverse array of gushing head wounds. The film is an unapologetically old-school action flick, with more attention paid to the mechanics of two men dueling with fire axes than nuances of personality. Once the screenplay establishes that Kang digs up information with his smartphone while Bobo prefers to interrogate witnesses by threatening their nostrils with garden shears, the script considers its obligations to establishing character fulfilled.

Writer Alessandro Camon (“The Messenger”) serves up dialogue as tight-lipped as Stallone’s face, which has received either extensive Botox treatments or a thick coating of shellac. “Guns don’t kill people. Bullets do,” he rumbles, though the film lovingly demonstrates the lethal potential of knives, automobiles, high explosives and even apples.

What keeps the killer and the cop together, other than shameless plot contrivance, is their protective instincts concerning Bobo’s lissome daughter Lisa (Sarah Shahi), and several common enemies. The long-absent Christian Slater returns to the screen with a smirky performance as a crooked lawyer and Jason Momoa, demoted after starring in last year’s ill-fated “Conan the Barbarian” reboot, plays a Goliath-like assassin. Both actors have the aroma of marked-down goods.

Exactly who is manipulating what in a scheme that requires so many corpses is unclear. It’s also beside the point. The purpose of the film is to prove that Stallone, now 66, can still inflict convincing beat-downs. Here he and Hill deliver the goods, with bruising, crisply edited brawls. The film is pure drivel, but it’s undeniably forceful, and a convincing testimonial to the power of whatever anti-aging regime its star follows. There’s a lot of female flesh undraped in “Bullet to the Head,” but none of it is ogled as appreciatively as Stallone’s fit, beefy torso.

Appearing a week after Arnold Schwarzenegger’s entertaining comeback in “The Last Stand,” and alongside the larky Al Pacino/Christopher Walken caper comedy “Stand Up Guys,” “Bullet to the Head” has the feel of a Monsters of Rock concert thrown together to cash in on the nostalgia value of its fading star. Hardcore fans will fist-pump, but the rest of us would have a better time slipping a disc in the player and re-watching his original hits at home.