In shooting circles, there are what are called "varmint rounds." These are specialized cartridges intended for shooting small, non-game animals that are essentially pests, including prairie dogs, ground squirrels, coyotes, foxes and rabbits, that are either a threat to agriculture or wildlife management, or are potentially dangerous. Most of these are small, high-velocity rounds with high lethality and low ricochet risk.

One subset of varmint rounds are cartridges that don't use bullets. Instead, they have a small plastic compartment containing tiny bird shot that scatters when fired. These can be loaded into a standard revolver, turning it into a little shotgun and is particularly useful against small, fast targets that you really want to hit the first time. I use them myself when I'm hiking in rattlesnake country just in case I come up against a herpetological hazard complete with nasty great venomous fangs.

It's a concept that lends itself to anti-drone warfare where a shotgun blast can have a decisive effect against First Person View (FPV) drones and commercial quadcopters. Unfortunately for the infantry, shotguns aren't something that every soldier can carry as standard equipment. Worse, shotguns have limited power and a pretty slow rate of fire even if they're semiautomatics.

Developed by Drone Round Defense, the Drone Round takes 5.56 x 45 mm NATO and 7.62 x 51 mm NATO rifle ammunition and turns it into a multi-piece projectile. At first glance, it looks like any other rifle round, but inside it has five to eight mini projectiles that deploy and are capable of taking out small drones at a range 50 to 100 m (164 to 328 ft), depending on the variant.

Not only does the scattershot of the multi-projectiles greatly increase the chances of hitting a drone, the NATO standard cartridge delivers a much heavier punch that is twice that of a shotgun, so one tiny bit of shot can be devastating. Beyond that, a standard NATO assault rifle has a rate of fire of up to 950 rounds per minute or a burst rate of 90 rounds per minute.

At the end of the day, this means that an infantry squad can simply swap magazines and suddenly be able to lay down a lead blizzard against incoming drones. In addition, the Drone Round can be used in belt-fed weapons like the M4 carbine, even with suppressors, without any modifications, so it can be used for flat-out sustained fire.

With all this in mind the US Army is now carrying out training for unit-level familiarization training with the Drone Round, indicating that the system has progressed to the deployment level.