There’s something uniquely satisfying about films, especially in the horror genre, that market themselves as “inspired” by true events. What does that even mean? It’s become common knowledge at this point that some of the genre’s most beloved entries that adopted this marketing ploy stretched the definition of inspiration one mile too far: A tragic shooting-turned ghost story became a cinematic legacy of demonic predation with “The Amityville Horror” series; likewise, shreds of Ted Bundy’s grisly murders map themselves onto “The Texas Chainsaw Massacre” baddie Leatherface.

“Winchester” is the latest film to get moviegoers’ salivary glands going crazy at the thought of a ghost story grounded in reality, but we (hopefully) know all too well that it’s code for laughably climactic ghost confrontations and jump scares aplenty.

Directed by the Spierig brothers (“Predestination,” “Jigsaw”), the film’s “true events” concern Sarah Winchester (Helen Mirren) and her enigmatic mansion in San Jose, CA. Grief-stricken following the death of her husband, the heiress to the Winchester Repeating Arms Company constructs a labyrinthian mansion designed to house the spirits of those killed by the Winchester rifle. In 1906, medical doctor Eric Price (Jason Clarke) is called upon by a representative of Winchester Repeating Arms to determine whether or not the spooked widow is mentally sound enough to run the company. Once there, he encounters spirits both benign and evil, shaking the skeptical man of medicine to confront the realities of his situation.

What makes “Winchester” so painful to discuss is the potential the Spierig brothers present in the film’s first half. Barring jump scares, the pacing is excellent. As far as haunted house setups go, the Winchester mansion is a seemly environment to mine effective spooks from. When the film isn’t busy setting up traps for its underage viewers (reminder: A PG-13 horror film is meant to satisfy no one but its MPAA-approved demographic), it’s creeping along well-lit and marvelously adorned interiors. Cinematographer Ben Nott is given just enough freedom to shoot the mansion from eerie angles that highlight just how perfect Victorian-era buildings are for horror locations.

We’re led to believe that the film has an operating brain when the motif of gun violence is introduced early on. The nature of the widow Winchester’s trade is inherently bloody — as she says, the success of her product is measured on its ability to indiscriminately end another’s life. She attempts to make amends with the specters roaming her house by allowing them to possess her momentarily, drawing diagrams of the rooms they were murdered in so that she could add them to her ever-expanding maze of a home.

If you could ignore the laughably cliche scares, it’s not out of the realm of possibility to read the film as a psychological horror that explores how grief has conjured ghosts — tangible or otherwise — into the lives of Price and Winchester. But it’s a lot stupider than that. Our antagonist is a disgruntled Confederate soldier whose brothers’ deaths at the hands of Winchester rifle-wielding Union soldiers turns him into a vengeful spirit who haunts the mansion. At midnight, ghosts get powerful (for some reason), possessing the innocent and scaring those foolish enough to go for a night stroll investigating creaky corridors. Also, apparently you can shoot ghosts with a rifle. So much for nuance. What begins as a promising horror film about rising gun deaths through the lens of one guilt-ridden superstitious gun merchant — merely bogged down by run-of-the-mill jump scares — devolves into inscrutable vacuous genre cliches with no more merit than the next soulless title.

For what it’s worth, “Winchester” owes its overall failure to little more than the awfully written script and genre cliches. Mirren and Clarke are the rare bunch of leads that treat their ridiculous script with earnest. By the time I checked out, they were still giving it their all. Mirren is an Academy Award winner — we expect her to excel. On the other hand, Clarke is her equal. While his character’s arc is underdeveloped, the performance he delivers is almost gripping and does nothing but bolster the material. In the hands of other performers, the film could fare much worse.

Verdict: “Winchester” somehow manages to do a disservice to the lore of its namesake mansion. It’s not offensively terrible, but its narrative failures overcome the strength derived from its solid lead performers and engaging beginning.