Marines using Drone Rounds in FATS/ISMT system trainers
The InVeris FATS (Firearms Training Simulator) and later ISMT (Indoor Simulated Marksmanship Trainer) systems have been used by the military going back to the 1980s. Besides giving some (virtual) trigger time in a safe indoor environment, the latter is key for bases with extreme summer or winter climates; they allow for real-time feedback and the use of more exotic scenarios than can be staged on a flat range.
Plus, they are fun. I’ve had a blast on them in the past.
U.S. Marines with 1st Battalion, 25th Marines, forward deployed with 4th Marine Regiment, 3rd Marine Division as part of the Unit Deployment Program, fire an M249 Squad Automatic Rifle light machine gun while conducting an Indoor Simulated Marksmanship Trainer at Marine Corps Air Station Iwakuni, Japan, Apr. 29, 2026. The training is a computer-based, 3D interactive simulator used to train Marines in marksmanship, tactical decision-making, and weapons handling without the use of live ammunition, while also being able to replicate various combat and range scenarios. (U.S. Marine Corps photo by Sgt. John Simpson)
Well, in a great case of “train as you fight,” the Marines have just bought 400,000 5.56 NATO L Variant counter-UAS cartridges from Drone Round Defense, with another million on the schedule for FY27. The Marines already field the real thing downrange for use in M4s and M27s.
From the press release:
That fielding timeline created an immediate training requirement. Counter-UAS engagements demand a different skill set than conventional marksmanship, including target lead on fast-moving aerial threats at close range. Live rounds issued to units are intended for operational use, not familiarization.
As part of the Marine Corps’ Indoor Simulated Marksmanship Trainer (ISMT) Tech Refresh, InVeris will introduce a new counter-unmanned aircraft systems (C-UAS) training capability. This enhancement will enable Marines across the force the ability to engage with aerial drone threats with their individual weapon in a simulated environment. By integrating C-UAS training with the M27 IAR simulator and fielding it across more than 200 ISMT systems, Marines will be able to repeatedly practice detecting, tracking, deciding when to engage, and engaging aerial threats. Because the capability is built on InVeris’ existing COTS platform, additional scenarios, threats, and courses of fire will continually be developed as the UAS threat and Marine Corps tactics, techniques, and procedures evolve.
“The round was built so a Marine could use the rifle already in their hands, and the training has to work the same way, on the simulators already in the building. Getting the virtual capability out at the same time as the ammunition means a Marine can practice the engagement before the moment they need it.” said Kirk Fernandez, co-founder and CEO of Drone Round.
“This partnership reflects the innovation the Marine Corps needs — taking the training infrastructure they already trust and readying it for Counter-UAS defense. InVeris is proud that our platform allows us to build this capability into the ISMT Tech Refresh rather than standing up something entirely new. This is what it means to grow with our customer’s mission,” said Clyde Tuggle, CEO of InVeris.
The Marine Corps has been building counter-drone proficiency into general-purpose forces through 2026. The service introduced its first counter-small unmanned aerial system lanes during Service Level Training Exercise 4-26 in July at Marine Corps Air Ground Combat Center Twentynine Palms, with Marines engaging aerial targets using organic small arms alongside non-kinetic electronic warfare techniques. Soldiers with the U.S. Army XVIII Airborne Corps have trained with Drone Round ammunition since April 2026.
The L Variant separates into five projectiles after firing to increase the probability of a hit against small drones. It is effective out to 100 meters, requires no modification to standard 5.56mm NATO weapons, and is full-auto and suppressor-capable. Drone Round has also developed L and K Variants in 7.62x51mm.