“It’s not a senate committee.”

For those waiting for Ben Wheatley to make a four-hour-long drama about the memories of his childhood dog, you’ll have to wait. The famed director joked after the U.S. premiere of Free Fire that he already shot such a movie with Sharlto Copley, claiming it’s now five hours long and full of shots of the sea and not much else.

Free Fire is basically the antithesis of such an absurd concept. It’s a brief 90 minutes comprised of a 15-minute introduction and five more minutes of peacetime, while the rest is a diverse baker’s dozen people shooting at each other after a gun sale gone awry.

Like any war, it’s a shootout started by one guy messing around with the wrong guy’s younger sister. The lesson to be learned: don’t try anything with Jack Reynor’s fictional sister, he’s bound to shoot you and start the equivalent of the Battle of the Bulge in an abandoned warehouse during an international gun deal.

Tensions were already starting to stretch thin as Chris’ (Cillian Murphy) gun order from the South African slang-slinging Vernon (Sharlto Copley) wasn’t exactly as ordered, making paying his order of M16s that turned into AKs a little hard to swallow. Adding in a personal storyline from one of the last members to show up was the final straw before the entire party turned into a smoking barrel special.

After directing what was supposed to be an unfilmable book with High-Rise last year, Free Fire might be Wheatley’s boldest feature yet and for some time (I’m not holding my breath on that four-hour drama). It takes a lot of brass to keep an audience’s attention on a gun fight for over an hour without advancing the plot beyond paradigm shifts among the characters as they shoot at each other, crawling on the ground as more blood spills than at a slaughterhouse.

Free Fire is largely character-driven instead of plot driven. Copley’s Vernon may be the biggest scene-stealer in the show, using Towie-South African sensibilities, but Reynor’s brash Irish attitude hits the right marks too. Murphy is almost unrecognizable as Chris, the British part of this equation going. Brie Larson stars as the American and only female voice in the middle of this international affair, while Armie Hammer acts as the moderator of this transaction. They too have scene-stealing moments, as Larson lets loose and shows a wilder side to herself, crawling her way through the rubble mostly caused by her coworkers’ machoism.

Since Free Fire is mostly about the shifts in the power structures once the shit hits the fan, the screenplay mostly relies on one-liners from the entire cast (though mostly in the hands of Hammer and Copley) to drain out the gunshots in the background. That said, this is one of the best sound-designed films in quite some time, and calls for surround-sound to be truly felt.

As Reynor or Hammer send out their shots, Wheatley’s design moves the sound across the entire theater, putting the audience right in the middle of this free fire. With a total of over 7,000 rounds used during filming, it’s miraculous to think it all still came together on a technical basis, which gives even more credit to Wheatley’s co-editor and writer Amy Jump.

To Wheatley’s greatest credit, though, this isn’t a film that can be described as well as it can be seen. There are too many films out today that can be summarized with just a few sentences. It’s high-concept invading the industry. While this could also be classified as a high-concept, experimental film, it’s best seen on the screen to take in all its importance taking on the sensitive topic of gun regulations in America head-on.

But without the likes of Copley and Hammer dragging themselves through mud, and the former literally being set on fire, it would be nowhere. With veterans like Murphy and Larson also in the line of fire, it’s safe to try new techniques — they hardly, if ever, make matters worse. Larson only propels the female power she has long been advertising. It’s great to see Wheatley put that to full effect, showcasing Larson’s talents once again.

And who doesn’t dig John Denver’s “Back Home Again?” You’re in luck, because you’ll have two chances to sing along — the last being funnier than the first. If you’re not a fan, it’s an hour of blissful chaos either way.