The U.S. Army recently announced that its Natick Soldier Center had received a request for a backpack that would carry 500 rounds of linked 7.62mm machine-gun ammunition, and a sleeve that would feed that ammo to a M240 7.62mm carried by soldier wearing the backpack. That much ammo weighs about 16 kg (35 pounds). In less than seven weeks, Natick produced the requested item and called it the Ironman Ammunition Carriage System. Such a pack would not be used all the time, but for situations where the longer range M240 machine-gun was needed, and there expected to be a lot of fighting, the Ironman was very useful.
But over a year ago, a commercial firm, TYR Tactical, offered for sale (at $4,000 each) an almost identical item (MICO Machine Gunner's Assault Pack). The TYR pack used a longer sleeve (from the pack to the M240), which contained another 75 rounds (for a total ammo weight of 18.4 kg/40.5 pounds). The pack itself only weighs a few kilograms (under ten pounds).
It’s still unclear if Natick copied the TYR assault pack design. The idea has been around for a long time, and troops have put together improvised assault packs in the past. TYR produces gear for SOCOM (U.S. Special Operations Command) and SWAT teams, while Natick fields request from all army units.
