HICAR – everything for “Lethality”

Everything is bigger in America. And faster. And farther. And anyway, with the NATO standard, you get the feeling they don’t do things that way anymore. First there was the NGSW program with 6.8x51 and the new M7 assault rifles, and now the XM8. And now this: The U.S. Special Operations Command (USSOCOM) has issued a request for proposals calling for a weapon to replace the current M4A1 URG-I. What’s exciting here: the requirement is to fire effectively with 5.56mm ammunition at ranges of 600 meters and beyond. This can be seen on the procurement platform SAM.gov. The goal is to integrate advances in materials science and weapon design to provide the military with a more technically advanced individual weapon system.

The program is called “Hypervelocity Improved Carbine” (HICAR). It involves the development of an improved carbine capable of firing both existing 5.56 NATO ammunition and future 5.56×45 mm hypervelocity rounds. The design is intended to ensure the weapon’s reliability, durability, and service life when using such ammunition.

Key Features of the HICAR

The new assault rifle must be compatible with 5.56×45 mm rounds and be capable of mounting and operating on the M4A1 platform without irreversible modifications—in other words, it requires an upper receiver that can be easily attached.

The HICAR must fire and function with M855A1, Mk262, and M855A1+ hypervelocity ammunition with pressures up to 82 kpsi, as well as with future hypervelocity ammunition types. The barrel must be 11 to 12 inches long, measured from the open muzzle to the breech face. The HICAR must use the HUXWRX Flow 556k L suppressor in the Black Magic version to reduce visibility until requirements for an optimized suppressor are established. Accuracy when firing without a suppressor must not be worse than one minute of angle (1 MOA). An accuracy of 0.5 MOA is preferred.

The weight without ammunition and without a silencer must not exceed 8 pounds (3.63 kg), preferably 6.5 pounds (2.95 kg). The length, measured from the end of the stock tube to the end of the muzzle device, must not exceed 31 inches, preferably 28 inches. The barrel life must be at least 8,000 rounds, preferably up to 20,000 rounds of M855A1+ ammunition. The weapon must remain fully functional in all environments at temperatures between -40 °C and 73.9 °C.

If the prototype is manufactured outside the United States, the developer must submit an industrialization plan for the production of the HICAR in the United States prior to contract signing. In accordance with this plan, selected suppliers will be invited to present and demonstrate their products in September 2026.

The call for proposals is likely also intended as direct criticism of the NGSW program. Even though the XM8, the lighter carbine version, will begin being issued to units starting in October, special forces do not believe in SIG SAUER’s concept. The fact that they are revolutionizing the existing M4 with an upper receiver featuring optimized barrels and bolt assemblies to create a lightweight weapon with an effective range of over 600 meters is quite remarkable, especially since this only works with hypervelocity ammunition. The HICAR program is also exciting for the regular army: after all, they have up to 700,000 M4A1s in their depots.