"The M27 that the Marine Corps currently uses for the IAR, is “hands down, the best automatic rifle in the world,” said retired Army Maj. Gen. Robert Scales, author of the 2016 book “Scales on War: The Future of America’s Military at Risk.”
“It outclasses the M4 in every single category,” said Scales, who is not affiliated with Heckler & Koch.
“The key category is reliability — particularly in dusty, sandy, muddy terrain. The HK has a solid rod system, like the AK-47.”
The M27, sold to civilians and overseas as the HK 416, uses a piston to control the function of the bolt, and that eliminates problems with gas-tube operating systems used in the M4 carbines and M16 rifles, according to the company’s website.
“If you have a solid rod, then the action can literally blow through things that would normally slow down a bolt action, because you’ve got more mass,” Scales said in a March 27 interview.
“Whereas, the M4 has a floating bolt that’s not attached to the rod. The gas goes down a long, thin tube — and the gas itself blows against another tube on top of the bolt, which throws the bolt back instead of carrying the bolt back.
The HK 416’s floating barrel makes it much more accurate and stable than the M4, especially in automatic fire, he said. The rifle also gives troops between 100 and 150 extra meters of effective range than the M4. “It’s the only weapon better than the AK-74, according to people I’ve talked to,” Scales said.
All of the technical innovations that make the M27 a modern and complex weapon also make it more expensive than the M4 — which has an operating system originally designed in 1955. And the M27 is also a very popular weapon, which drives up the price, Scales said. ”