An older article over at Defense Review (written by Mike Pannone) discusses the question of whether or not direct impingement gas systems result in excessive fouling, which ultimately makes the M4 platform unreliable.
Essentially it’s a Myth Buster style look into the age old argument that an M4 direct impingement gas system is essentially shitting in it’s own nest via the blowback operation and therefore will cause lots of fouling which in turn will at some point cause a failure.
Mike writes: “I fired 2400 rounds of M193 through a 14.5” M4-type upper receiver from Bravo Company Manufacturing (BCM) with no lubrication, and without any rifle-caused malfunctions. So; why can I get my direct impingement rifles to repeatedly do things that conventional wisdom says they can’t do?”
I admit that I’ve always heard, and believed, that the direct impingement system is to blame for many of the M4’s failures. This is a must read for any enthusiast and damn good reading for anyone else! Kudos to Mike and Defense Review on a substantial contribution to the topic.
Read the full article here: The Big M4 Myth: ‘Fouling caused by the direct impingement gas system makes the M4/M4A1 Carbine unreliable.’