The FN IAR is based on the SCAR. It has a rate of fire of 650 RPM and weights in at 10.4 lbs.

    Picture 4-20
    FN IAR. Click to expand.

    One very interesting features is that it switches automatically from closed bolt to open bolt depending on the chamber temperature. From FNH-USA:

    Today FN offers the new Infantry Automatic Rifle (IAR), a unique, highly-adaptable, modular selective fire weapon system that fills the roles of both individual battle rifle and squad automatic weapon in one light, compact package. The magazine-fed FN IAR is capable of firing from a closed bolt in both semi-automatic and fully-automatic modes, yet automatically transitions into open-bolt operation in semi-automatic or fully-automatic before reaching cook-off temperature for a chambered cartridge.

    I do not think the temperature switch would be electronic. Most likely there is a piece of metal that expands when heated and causes a switch from closed to open bolt.

    Again, a bit thanks to Daniel Watters for pointing this out to me.

    Steve Johnson

    I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!