The U.S. Marine Corps have battle tested the M27 Infantry Automatic Rifle (IAR) in Afghanistan and intend to purchase more of these to eventually replace the M249 LMGs that are in service in the Corps. There have been discussions that the M27 IAR, whilst based on the HK416D, is much more different from the latter. But Military Time's Gear Scout does us a service by providing us a video of the M27 IAR and indicated that there's not much difference between it and the HK416D, albeit some small design changes that are based on USMC requirements:

To reiterate what has been mentioned in the video: there are some marking difference, an 11" free float handguard versus the 9" on the HK416; a 16.5" barrel; with the longer handguard, they adjusted the bayonet lug further from the gas block; the charging handle is ambidextrous and can be adjusted for left hand shooters; and the firing pin is retained.

Also a revelation in the video are the type of magazines that can work with the M27 IAR apart from the authorised USMC magazine. The Magpul PMAG cannot work with it but the EMAG does, and the 5.56 magazine designed by Heckler & Koch for the HK416 works perfectly with it. The Surefire high capacity magazines, especially the 60-round have been tested with it and does work and the 100-round version can fit, though has not been tested yet by Gear Scout.

Thumpy may want to suggest to Crosman, if indeed he gets to talk to them, to actually work on the M27 IAR airsoft version since they own the licence in using the USMC brand for airsoft. If indeed they do, then this will be the first serious airsoft gun that would surely get an audience with the serious airsoft players.

I do hope that Crosman's reading this, it would be fantastic to have an official USMC M27 IAR for airsoft that can be found at Marines Airsoft.