Bye, Bye M4 Carbine

Bye, Bye M4 Carbine
By Charlie Cutshaw

AmmoLand Gun News
AmmoLand Gun News

Florence, Alabama – -( It’s no great secret that the Army’s M4 carbine hasn’t exactly covered itself with glory in Iraq and Afghanistan.

As long ago as the 1960s, long before the M4, the issues with the M16 rifle version of the AR design were well known.

In Vietnam, the M16 quit functioning so frequently that many photos from the mid-60’s show soldiers and Marines with cleaning roods taped to their rifles to clear cartridge casings that failed to eject.

The root cause of the M16’s reliability issues were the Ljungmann direct impingement gas system that in the words of some, “vomits into its own mouth.”

The cure in Vietnam was heavy lubrication to keep the fouling soft coupled with frequent maintenance. After over 40 years as, the AR platform continues to be a “dirty” weapon and its reliability has only been worsened by the large scale changeover to 14.5 inch barreled M4.

(Actually, there are two versions of the M4 – the base M4 that is semiautomatic or three round burst capable and the M4A1 that is capable of full auto fire. The latter is used primarily by Special Forces, while the M4 is predominantly used by “Big Army.”)

The issues inherent with the M4 were long ago reported by the first units to use the weapon – IE: Special Forces.

In fact, a 2000 SOCOM study regarding the M4A1 stated in part, “All…M16-based carbines and the M4A1 are fundamentally flawed.”1

Problems identified included failures to extract, broken bolts, burst barrels, cookoffs, loosened barrels and in extreme cases, blown receivers. In addition to these problems, both carbines have reliability issues in a desert environment engendered by the need to keep them heavily lubricated because of the fouling engendered by the direct impingement gas system. In the “sandbox” environment of Afghanistan and Iraq, the lubricant becomes a “dust magnet,” actually attracting the fine talcum powder like sand that seems to get into everything. When combined with the lubricant, the dust turns into a “goo” that brings cycling to a halt, which isn’t exactly what one wants or needs in a firefight. The same is true if the carbine is run dry, since it depends on lubricant to function.

HK XM8 Modular Assault System Rifle
HK XM8 Modular Assault System Rifle

The reports of malfunctions and the issues mentioned above led the Army to evaluate alternative carbines in 2007 in an environment as close as possible to that encountered in desert combat zones. Ten sample carbines of each of four candidates were test fired for a total of 6,000 rounds each. It isn’t our point here to go through the exact test procedures, but the test protocol was fairly close to “real world” operational conditions and when the dust settled (No pun intended.), the Colt M4 was dead last with 882 stoppages/malfunctions. The next worst, H&K’s 416 had only 233 disabling stoppages. The Mark 16 SCAR was almost in a dead heat with 226 stoppages. Best was the XM8 with just 127 stoppages. Of course, the XM8 program was long ago terminated by Congress because it had been concluded that it didn’t do anything significantly better than the M16 rifle, so just why the XM8 was even included except perhaps as a baseline is questionable.

By late 2008, the Army bureaucracy decided that what was needed was an entirely new carbine to replace the M4 family, although the problems with the M4 were restricted to the upper receiver that attaches to the lower receiver via two pins.

What this means is that the upper receiver can be replaced in a matter of seconds by simply pressing our the two retaining pins, dropping on a new upper receiver and pressing the pins back in to lock the new received in place.

POF-USA P416 14 11sx 223 Rifle
POF-USA P416 14 11sx 223 Rifle

This is a VERY important point.
Special Forces long ago began solving the M4’s inherent issues by just dropping on a new upper receiver that eliminated the direct impingement gas system and replaced it with a gas piston and operating rod. This was Heckler and Koch’s HK416. But there was an issue with the HK 416 as well. Although not widely reported, the HK416s operating rod return spring that was in close proximity to the carbine’s chamber area could be damaged by heat. An alternative that was never formally procured by the military was Patriot Ordinance Factory’s P416 that not only uses a piston and operating rod, but runs without any lubrication whatsoever. We know of at least one Special Forces Team that deployed to Afghanistan equipped entirely with M4A1 carbines with POF 416 upper receivers. One of the officers on this team, who must remain anonymous, informed us that the POF equipped carbines had virtually zero stoppages and weren’t affected by the dust. Informal feedback from other POF combat users indicates that the weapons deliver almost unbelievable levels of reliability and longevity. We have conducted long term testing of semiautomatic versions of the POF system in both .223 and .308 and can attest to the fact that it runs without lubrication of any kind and that the receiver remains remarkably clean and virtually free of fouling.

In November 2009 the Army invited 19 small arms manufacturers to an “industry day” in Washington, DC in an effort to see what industry was capable of producing. At this point what the Army will do about the M4 isn’t clear, but we believe that one point is worth mentioning – there really is no need for a completely new carbine like the Mk 16 SCAR, because whatever issues there are can be rectified without spending the millions needed for an entirely new weapon.

Vltor Weapons Systems Modstock
Vltor Weapons System’s Modstock EMOD Combo Kit – Flat Dark Earth

The dust, lubrication and heat problems can be resolved by purchasing the POF P416 upper receiver that just drops into place. If a new caliber like he 6.8mm SPC is wanted, that is as easy as changing upper receivers as well. If users don’t like the cheek weld on the M4’s collapsible stock, stocks with cheek rests better than the fixed stock M16 are available. An example is Vltor Weapons System’s Modstock. Again, we have used the Modstock extensively on our personal POF carbine that rides in the trunk of our cruiser at the police department and recommend it to anyone who has an M4 type carbine, whether semi- or full auto. You’re right, gentle (or not so gentle) reader, we like POF carbines and Vltor accessories, but we have the opportunity to shoot a LOT of AR-type carbines and these are the ones we prefer over all others.

The bottom line is that the M4/M4A1 as currently configured isn’t going to be around much longer. As the eight year old SOCOM study stated, the design is “fundamentally flawed” and should long ago have been redesigned or replaced.

An New Carbine Is Not Necessary
To reiterate, an entirely new carbine is neither necessary nor desirable. The M4 design is well known and spare parts and suppliers are in place. An entirely new weapon would necessitate not only new weapons production, but new spare parts production as well, with duplicate parts inventories being necessary for years to come. Moreover, the M4/M4A1’s issues are capable of being rectified in a fraction of the time and at a fraction of the cost of an entirely new weapon. (Related News: See also Adams Arms AR15FIX Retro-Fit Piston)

Finally, the technology already exists to upgrade the M4/M4A1 to the levels of reliability that our nation’s soldiers deserve. It has been said that getting anything done in the Army bureaucracy is like mating elephants – it is done at very high levels with a lot of bellowing and it takes two years to get anything done. The Army bureaucracy long ago identified the M4’s problems, the bellowing has been going on for over eight years and our soldiers are still plagued with the same “fundamentally flawed” carbine they had when the problems were identified. It’s very close to a national scandal that many of our troops are forced to obtain high reliability upper receivers like the POF 416 on their own!

It’s high time for the Army bureaucracy to quit dithering and get something done to give our troops the weapon they need and deserve!

Charlie Cutshaw
Charlie Cutshaw

About the Author:
Charlie Cutshaw is a well-known U.S. authority on military small arms and has an extensive experience as a former U.S. Army infantry, ordnance ammunition and intelligence officer. He is an editor for Jane’s Infantry Weapons and contributing author for other military and firearms publications. When not writing Charlie is a part time police officer in Alabama. Si vis pacem, para bellum MOLON LABE!

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3 years ago

Some inaccuracies in this article. The M16 did not have problems with the gas system itself. Some genius decide to switch powders for the ammo being used which changed the pressure spike when firing. This caused the case to try to extract during full expansion. This was the cause of the failures you mention and why they had to use cleaning rods to knock out jammed casings. Had the last minute powder change not occurred, the weapon most likely would have functioned 100%. There is a great documentary on this featuring one of the engineers that helped design and build… Read more »

Bruce Ponder
Bruce Ponder
6 years ago

Precision Ordinance Factory? Really? Never heard of them! But I do own a POF made by Patriot Ordinance Factory.
Don’t use spell check. Hire a proof reader. And you put it in the paragraph labeled “This is a very important point”