An independent gunsmith working out of a garage in Colorado has invented a potentially revolutionary new rifle, and it's got the US Army's attention.

Martin Grier's L4 "ribbon gun" combines four bores in one barrel. In other words, its business end has four holes instead of one, and can simultaneously fire up to four bullets.

That's not the L4's only possible advantage over existing guns. It also could be easier to carry, fire and clean than existing weapons are. "The L4 is the first of a whole new class of weapons," Martin Grier told me.


Ben Grier, Martin’s brother and partner on the L4, said the Army wants to test the new rifle. “We met with the Army twice and they are interested,” Ben said. Martin is working on finishing what Ben described as a new “military-grade” version of the L4 for the Army to experiment with.

The L4 is just one of several gun designs the ground-combat branch has considered in recent years as it attempts to replace older weapons.

But the L4 stands out, Martin Grier said. All the other submissions to date have been “mere variations on the single-bore theme, not enough better to justify a wholesale changeover.”

The Army didn’t immediately respond to multiple requests for comment.

The L4's newness is the secret to its appeal. But that same novelty could prove to be a big problem as the Army struggles to acquire a new rifle that it can mass-produce at reasonable cost and deploy with minimal disruption.

Grier reportedly spent $500,000 developing the L4 and building the initial copy under the auspices of his company FD Munitions.

Grier is in his 60s. He never served in the military, but he grew up around guns. "I did a lot of shooting, reloading and gunsmithing, starting at a very young age with the family guns, and then with everything I could get my hands on," he told me.

It occurred to him that all the guns were essentially the same. A single barrel, and ammunition that came packed in detachable magazines. "No real innovation had occured since the time of John Browning," the legendary gun-designer who died in 1926, Grier said.


At least one military official has echoed the same sentiment. "It's time to upgrade," John Bednarek, a retired Army general, told a Senate subcommittee during a 2017 hearing on military rifles.

The US military's main rifle is the M-4, a lighter version of the M-16 that's been around since the Vietnam War. Both the M-4 and M-16 are conventional weapons with traditional rifle layouts. They're notorious for their tendency to jam and the limited stopping power of their old-style ammo.

Despite the existing rifles' drawbacks, the military repeatedly has failed to come up with replacement weapons that are worth the billions of dollars it would cost to equip US troops. So the armed forces have made do with small upgrades, most recently modifying its rifle ammunition to fly faster.

But the Army is getting tired of merely tweaking 100-year-old technology. "The Army, to its credit, is not interested in change just for the sake of change," Grier said. He claimed his ribbon gun represents the radical departure the Army says it needs.

Besides its four bores, the L4 ribbon gun has fewer openings that could allow dirt to get into its moving parts, making it easier to clean. At six pounds, it's also slightly lighter than an M-4 is.

The L4 also features a new kind of ammunition: a solid block, roughly the size of a deck of cards, that holds four six-millimeter-diameter rounds. A side-mounted device feeds a block at a time into the weapon, neatly aligning the four projectiles with the four bores. The mechanism allows for a potentially very high rate of fire compared to older weapons.

Grier told me that if the Army adopts the L4, it can expect "a large increase in the overall capability of the ground forces, resulting from the new weapons and the new tactics made possible by those weapons."

But there's a catch. The Army's bureaucracy is set up to spend years or even decades carefully examining potential new weapons before approving them for widespread use. Ditching a rifle with a century-long lineage for a truly new-style weapon could prove too big a move for such a risk-averse organization.

To get a new rifle into soldiers' hands, one retired general told the Senate subcommittee that it should consider bypassing the bureaucracy. "I think we need to find a way to wire around the acquisition system," Robert Scales, the former commandant of the Army War College, said at the 2017 hearing.