FNH USA has released the Heat Adaptive Modular Rifle (HAMR) at AUSA. Based on the FN SCAR 16 platform, the system was a contender for the USMC’s Infantry Automatic Rifle but lost out to the HK M27 which is based on the 416. FN claims that the HAMR is accurate to 1 MOA but did not differentiate if this was from an open or closed bolt. Additionally, FNH has announced that the HAMR boasts a controllable 650 rpm rate of fire.
So exactly what makes the HAMR unique? The capability presented is best described by FN’s own press release, “FN HAMR initially fires from the closed bolt in either semi-automatic or full-automatic modes. For added safety during sustained fire situations, the FN HAMR automatically transitions into open-bolt operation in both semi-automatic and full-automatic modes before reaching the cook-off temperature of the chambered cartridge. Once the chamber temperature has dropped to a safe level, the FN HAMR automatically transitions back to closed-bolt mode. These transitions between closed-bolt and open-bolt modes are thermally regulated by the FN HAMR and occur without any manual intervention by the operator.”
Ambitious, but it seems as though there is a certain amount of technical risk here. Whether the mechanism that transitions the weapon’s operating system from Closed to Open bolt is electrical or mechanical like the thermostat in your car’s cooling system, it is just one more thing to go wrong. However, the SCAR itself is the most tested rifle in the US military’s history and it is doubtful that FN would have brought the HAMR to market if it wasn’t ready for prime time. We will be interested to see how they went about managing the operating system.
We understand that the IAR candidate had a heat sink built into the design so the HAMR’s stated weight of 11.2 lbs is also of interest but this includes a Grip Pod. On a final note, as it is being offered as a full-auto weapon for military and LE use, the average shooter will never have access to the HAMR. However, we are glad to see that the technology is being commercialized in one form or another.