[brightcove video="1231373470001" /]
Here's a quick video showing the differences between the USMC spec'd M27 IAR and the HK416 and its compatibility with aftermarket magazines. First, there's a little confusion about the IAR variant being considerably different than the HK416. As you'll see, the differences are minimal. There's no heavier barrel and the internals are identical to the HK416D. The IAR is pretty much a 16.5" HK416D with a bunch of accessories required by the Corps. Run through the gallery below for a closer look at some of the differences and unique features common to the HK416 and the M27 IAR.
Second, there's a question of what mags work in the gun. While I didn't get to full function check the mags in the gun, rumors about the Surefire HCM not fitting are wrong. You can see both Surefire mags fit and fall free with no issues. I haven't shot the 100 rounder yet, but we've heard the 60 rounder runs fine. Surefire's official response is that they didn't design the mag to work with the gun, although they have heard some samples fitting in the HK416 and some not.
I'm hoping to get some range time with the gun and a set of mags in the next couple of weeks to see how reliably the Surefire HCMs function in the HK416.