RRH’s Mil-Spec IAR

UPDATE: 1/28/2025 : Mil-spec IARs will return in March 2025 with our latest 14.5″ Block 4 Barrel and HMS.

The Creation of Red Right Hand’s Mil-Spec IAR

Infantry Automatic Rifleman is a concept adopted and used by the USMC. The program was to replace major use of the M249 belt fed Light machine gun. The end goal was to field a rifle that is light weight, accurate, use common magazines and capable of handling more heat associated with the role of Auto-Rifleman, Thus bridging a gap between the rifleman and the M240 Gunner. The M27 has become a beloved weapon in the Marine corps arsenal. Our goal was to create a version of the M27 IAR upper that would address issue with the current issued HK M27, the heat that builds up in its barrel during heavy use.

Red Right Hand’s Heat Mitigation System.

Similar to our RECCE LMG upper line, the RECCE IAR v1’s barrel is incased with our 6061 Aluminum Heats Sinks and the Stainless Steel gas tube is covered in our Copper/Nickel Alloy Heat Sink Coil. Our infamous Heat Mitigation System was purpose built to fit our new 14.5″ Block 4 barrel, and in testing we have seen insane numbers of heat reduction. Our system effectively puts this upper  into the Auto-rifleman role without sacrificing accuracy or reliability of the system. The Mil-Spec IAR upper welds just like a classic Block II style upper due to the profile of the barrel and minimal weight addition of the HMS.

Our new Block 4 barrel is manufactured by Shaw Barrels to achieve perfect integration of our Heat Mitigation System. Built with the Auto-rifleman role in mind, these barrels are 14.5″ long, Chrome-Lined, Feature a 1/7 Twist, are chambered in 5.56 Nato, and made with machine gun rated 4150CMV steel.

Red Right Hand’s HTB (Heat Transfer Block)

For the Mil-spec IAR upper we designed our own non-adjustable gas block to work with our famous Heat Mitigation System and lower the cost to entry without sacrificing the advantages of our design. Not all our customer’s desired the advantages of the adjustable systems found on the RECCE IARv1 or piston driven v2, some just want to run un-suppressed and we understand that.

Red Right Hand’s HTB is our simple designed non-adjustable gas block. Designed and Made to work with Straight Gas-Tubes and our HMS cooling system. This heat-treated 4140 gas block is installed with double dimples and Knurled Set Screws. One last trick up it’s sleeve is its coating… We have these coated in Cerakote’s Heat Transfer coating, this coating helps the steel shed heat faster than other available finishes! The increased ability to shed the heat was important to us, so this was an excellent choice.

The Mil-spec IAR uppers are gassed like any other properly gassed Mid-Length upper (.076 gas ports). When paired with different buffer and spring weights, end-users can find their desired ROF and ejection pattern with their chosen ammo. Otherwise these Mil-spec IAR uppers will behave like every other smooth shooting Middy rifle. For running un-suppressed, these are gassed great.

Mil-Spec IAR Production 2025.  All Orders placed are built to order. Orders will begin in March 2025. Uppers should ship 4-8 weeks from date of order unless noted above. Thank you for your patience.

Thank you for choosing Red Right Hand LLC!