The HK 416 is the Mercedes Benz of AR technology. They run very cool with the piston system under sustained fire conditions compared to a direct gas M16icon/M4. I handled and fired one once several years ago and was impressed but the truth is, I've never had a problem with the direct impingement system as originally designed by Gene Stoner. There are less moving parts and the weapons will run just fine with proper cleaning, care and lubrication. There is a bit of a stink about what the USMC M27 will cost the taxpayers too. I think to the tune of $1100-$1200 per unit.