At Modern Day Marine 2018, BAE Systems displayed a more lethal version of an ACV. While the turret configuration hasn't been bought by the U.S. Marine Corps, the company is showing off potential in that area.

The Marine Corps is looking at a 30mm gun variant for its newest platform ― the amphibious combat vehicle ― and there’s a chance that weapon system will have the ability to switch to 40mm.

The firepower upgrade is mostly in industry experimentation right now, as the Corps is focused on the 30mm work, which includes the ACV manufacturer’s testing of a variety of guns and turrets.

The ACV family of vehicles will include a personnel carrier, command and control variant, a recovery version and the guns or 30mm option.

Marine officials are finalizing the requirements and performance specifications for the 30mm system that will go onboard the ACV, said Marine Col. Kirk Mullins, program manager for advanced amphibious assault.

“We continue to work with BAE to refine those and fully understand the design parameters for a system that we can integrate onto the ACV,” he said.

And it’s not as simple as slapping on a turret and the biggest gun that will fit.

“We’ve got to make sure whatever system we choose doesn’t impact vehicle performance in swim, land speed, etc. no residual effect on that,” Mullins said.

To figure out how it will all fit together, BAE has been evaluating a variety of options.

BAE Systems recently live fired in Arizona using MCT30 Remote Turret, used on the Army’s Stryker and made by Kongsberg along with a 30mm chain gun, Mullins said.

Mullins said that testing was strictly industry work and government officials were attending for observation purposes. Neither the turret nor the gun has been finalized yet.

But another weapon, the Northrop Grumman MK44 Stretch, was also put into the live fire.

The colonel said that weapon has the option of being switched from 30mm to 40mm simply by changing the barrel and feeder. But the focus now is on 30mm.

The MK44 has dual feed systems that can accommodate linked or link less ammunition feed, according to Northrop Grumman and rides mostly outside of the turret, providing more space for the gunner.

The weapon has most of the same features as the common 25mm M242 Bushmaster Cannon, weighs 350 pounds and can fire single shot, burst or fully automatic.

The Corps selected BAE’s version of the ACV about a year ago over the SAIC vehicle. BAE has been the only company to provide amphib vehicles to the Marines since 1941, John Swift, program director for BAE amphibious vehicles previously told Marine Corps Times.

They went with an eight wheel design over a tracked version, which was what the old amphibious assault vehicle used.

Reasons for that included greater mobility, better IED protection, less fuel use, greater reliability, increased dispersion and reduced signature, among others.

The first builds are focused on personnel carriers but the turreted gun ACV and the C2 variant are expected to go into production in the next two years, Swift said.

At the time, the Corps wanted 704 ACVs for its fleet with full production on early variants starting in 2022, Swift said.

The gun and C2 versions are planned for fielding by late 2024, early 2025, ACV spokeswoman Barb Hamby wrote in an email to Marine Corps Times.