Who authorized the “flying crew-served weapon” with increased recoil?
High above the floor of the SHOT Show, Colt’s most interesting display has not been a new rifle design or a shiny prototype behind glass. It is an operational concept: a SURVICE TRV-150 Group 3 unmanned aircraft system with a Colt Mk47 40mm automatic grenade launcher, in answer to an inquiry driven by the Marine Corps: how far can the resupply drone be stretched into combat without violating the laws of physics?
The TRV-150 has already proven itself as a tactical logistics platform and its performance specifications, available to the public, explain its frequent mention in the context of “multi-mission” drones. In 2023, the Marine Corps chose the TRV-150 for resupply missions, stating it had the ability to carry a cargo payload of up to 120 pounds in an autonomous configuration. This is significant because Colt’s proof-of-concept exhibit takes advantage of the same performance margin: the Mk47 weighs around 40 pounds, with enough room left over for mounting, power, stabilization equipment, and a substantial ammunition load. Colt has described this as a configuration that carries about 60 rounds of ammunition but still takes advantage of the TRV-150’s advertised 150-pound payload capacity and 45-minute endurance.
The combination of endurance and payload is easily explained, but the harder part is dealing with recoil. A drone that can support a crew-served weapon needs to maintain sensor and weapon stability between each shot. This problem has led to a number of different solutions in small drone weaponization, from simply dealing with the destabilization to a mechanical system to compensate for the recoil. One of the most telling ways of dealing with the problem is the “backward and forward” method used by shotgun-wielding interceptor drones, where the recoil is compensated for by firing a counterweight backward while propelling the shotgun pellet forward. The general lesson here is not the shotgun itself but the recognition that recoil is often the gating factor, not triggering or mounting a tube on a quadcopter.
The reality that Colt’s display implicitly recognizes is that of the TRV-150’s antecedents. The Marine Corps has been connected with trials involving the TRV-150 and 70mm rockets, and Colt has pointed out that the recoil force of the 70mm rockets is similar to that of the Mk47. If this holds true in terms of instrumentation and flight test data, then it would seem that the airframe design, mounting system, and control algorithms are already in a domain appropriate for a system which has a strong recoil force, as opposed to a single impulse.
The Mk47 itself also brings a certain flexibility that contributes to why this combination goes beyond the realm of mere novelty. Following Colt’s assumption of control of the system in early 2024, the company has inherited a weapon that is described as having the capability to function either as a conventional automatic grenade launcher or as a programmable airburst weapon through its fire control system. For a drone application, this flexibility is more about being able to get a certain effect with fewer rounds, thus overcoming the “ammo equals payload equals endurance” limitation that exists for unmanned aircraft.
Another factor that is quietly being introduced into the logistical mix is the autonomy that improves low-altitude flight and landing capabilities. The resupply mission of the TRV-150 has already utilized miniaturized autonomy kits, such as the Firefly system of Near Earth Autonomy, which is estimated to weigh two pounds and offers obstacle avoidance and other autonomy-related functions. These functions were intended to address the ability to navigate wires, trees, buildings, and ad-hoc landing sites; such capabilities also affect the survivability and viability of a larger armed UAV that flies at low altitude and repositions frequently with a limited operator capacity.
The SHOT display has not answered the question of whether a belt-fed 40mm system on a cargo drone will become an operational capability or a range novelty. It has, however, clarified the engineering question: not whether a TRV-150 can lift an Mk47, but whether the processes of recoil, fire control integration, and autonomy can be sufficiently tightly integrated to provide a stable weapons platform as opposed to a fleeting airborne gun platform.
