Franchise showing its age in ‘Expendables 3’

‘I haven’t had this much fun in years!’’ exclaims Harrison Ford, who somehow manages to keep a straight face during the final scenes of “The Expendables 3.’’

Good for him. Most of us have probably seen episodes of “Antiques Roadshow’’ more exciting than this PG-13-rated, interminably boring “action’’ fiasco.

With series regular Bruce Willis off collecting his hefty paycheck elsewhere, Ford is among the new recruits to the latest and least entertaining installment of this aging franchise about Sylvester Stallone’s over-the-hill gang of mercenaries.

Ford, a one-time member of that gang, is now a CIA handler who wants to bring in an arms dealer, played by Mel Gibson, who of late has been reduced to appearing in the likes of “Machete Kills’’ and, for all we know, dinner theater in Dayton, Ohio.

But anyone expecting the erstwhile Indiana Jones to go mano a mano with the former Mad Max is guaranteed to be disappointed.

Ford spends almost all of his carefully rationed screen time parked in front of green screens — grouchily barking orders into a cellphone from the back seat of a car, or grimly pretending to fire missiles from a plane into what looks suspiciously like buildings being demolished for an urban-renewal project.

All this while oddly immobilized martial-arts superstar Jet Li and an alarmingly rotund Arnold Schwarzenegger — who apparently requires a stunt double to simply walk across a set these days — look on approvingly.

Gibson, who appears as if he’s had a makeover at Madame Tussauds, spends a lot of time glaring — or maybe he’s just struggling to keep his eyes open through this thing like the rest of us.

After what feels like enough time for a double feature of “The Passion of the Christ’’ and “Apocalypto,’’ Gibson and Stallone — or possibly their stunt doubles — half-heartedly go at it in one of the most ineptly choreographed battles in recent memory.

Also joining the inaction this time around is Wesley Snipes, as a former team member they release after a decade imprisoned in direct-to-DVD movies — sorry, make that a Somali prison.

This Hollywood make-work project even throws in “Frasier” star Kelsey Grammer as a mercenary headhunter who helps Stallone recruit some younger (but even more boring) team members, like Kellan Lutz, Ronda Rousey, Glen Powell and Victor Ortiz.

Even with a two-hour-plus running time that’s more bloated than Schwarzenegger’s torso, Stallone’s original comrades — including second-in-command Jason Statham, as well as Terry Crews and Randy Couture — have little to do but fire off the occasional one-liner. Almost all of them, incidentally, are duds.

The first two “Expendables’’ were hardly great movies, but they contained enough moments of campy fun to make them passable entertainment in the dregs of August. This installment’s an unremittingly leaden slog that often plays like a promo reel for the film commission of Romania — which stands in here for a variety of real countries and fictional ones, like the hilariously named “Assmanistan.’’

And whose idea was it anyway to replace the red-blooded, R-rated action of the first two with the thoroughly sanitized violence that lowers the stakes to practically nothing?

Time to pull the plug on this brain-dead franchise. Maybe Gene Hackman, Sean Connery and Roger Moore can come out of retirement to exterminate it — hopefully, with extreme prejudice.