More reports on M4 limitations. Do the Marines have the right idea?

Steve Johnson
by Steve Johnson

A leaked US Army report about the Battle of Wanat criticizes the reliability of the M4. On July 13, 2008 200 Taliban fighters attacked 48 US and 24 Afghan troops. Outnumbered 2.7 to 1 the M4 Carbines, which the troops were carrying, could not function reliably under the sustained fire they were required to put downrange. Fox News reports:

The platoon-sized unit of U.S. soldiers and about two dozen Afghan troops was shooting back with such intensity the barrels on their weapons turned white hot. The high rate of fire appears to have put a number of weapons out of commission, even though the guns are tested and built to operate in extreme conditions.

“My weapon was overheating,” McKaig said, according to Cubbison’s report. “I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn’t charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down.”

Snowflakes In Hell, via Michael Bane’s blog, correctly points out that assault rifles are not machine guns:

No assault rifle is going to stand up to sustained automatic fire. They aren’t machine guns, and even a machine gun needs to have its barrel changed out if it’s been firing a lot.

The M4 has a very short 14.5″ barrel and a relatively lightweight barrel profile. This allows the barrel to heat up much faster than a longer and heavier rifle or machine gun barrel. When the barrel of a closed-bolt gun gets very hot, cook-offs,when a round is ignited from the heat in the chamber, become a significant problem … not to mention the fact that a soldier cannot fire a gun that is to hot to hold!

The Marines have been criticized by many for their plans to introduce an Infantry Automatic Rifle (IAR) into the mix of weapons issued to their troops. The IAR is not intended to replace the SAW but would be deployed alongside it, giving some riflemen a light weight weapon that can sustain automatic fire.

FN IAR. Switches from closed-bolt to open-bolt when automatically when barrel temperature increases.

The Army would do well to look into the concept.

At the end of last year the Marines announced they were awarding contracts for the development of IAR prototypes to Colt, H&K and FN. Since then I have heard nothing about the IAR.

There are discussions about the M4 failure at Wanat over at Snowflakes In Hell, via Michael Bane’s blog and SaysUncle.

Many thanks to Jerry, Caedis, Lee and Lance for emailing me links about this story.

Steve Johnson
Steve Johnson

I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!

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  • Regular guy Regular guy on Jul 17, 2014

    Another shameless use of a tragedy to sell something. The problem with this example is the break-down of the ROE, no real organic fire power in the platoon, and incompetence in the JOC’s in theater.

    1. If a mission commander briefs a fires plan; he has no idea if it will be allowed by “Leaders” too far from the fight if called for.

    2. Platoons cannot carry enough 7.62 or 5.56 ammo to sustain a long fire fight. The issue in theater is as an example; do you have a single bee or the entire hive today? The reasoning for point number one. Some Major in the JOC will assess if his PL is or is NOT in that big of a fire fight to avoid being responsible for collateral damage.

    3. No amount of 5.56, 7.62 or 6.8 solutions will fix what happened that day based on point number two. If the enemy can shoot an RPG 900m and a PKM 1000m; what do you think they will do knowing we don’t have the ability to return fire at that range to answer that threat within the platoon?

    The real issue here that our Infantry combat developers are avoiding is the removal of a cannon caliber weapon from the platoon, similar to our enemies RPG. This would allow a platoon to sustain its self until more help arrives. Offense and defense in layers used to be the logic in the old days of common sense. If my recoilless asset fires 900+m; I can control the fires of my riflemen and machine gunners until the enemy is within effective range of his weapons. No battle rifle will hold up to the current tactic of “Spray and Pray” for very long, no matter what the caliber is. Our soldiers can only engage just over 400m effectively with a good optic. This is the real issue! The enemy understanding this, magically prefers 500-600m or more to shoot from. The old M3 Carl Gustaf shoots a 6.8lbs 84mm round 1300m with a kill radius of over 10m. It weights 21lbs or 6lbs lighter than a M240B, shoots 400m farther than the RPG and our own M240B. The new Carl Gustaf weights 15lbs with the same range and lethality. This would give organic overmatch to the platoon and reduce its dependency on artillery, air support and it will eliminate the decision needed from the incompetent guy worrying only about himself and collateral damage to defend itself.

    • See 1 previous
    • Kivaari Kivaari on Aug 26, 2014

      @Regular guy Very well presented. Although I was infantry for a short time, soon becoming a REMF, I studied enough to know that spraying your ammo is not effective.
      Not having reach with a mortar or recoilless rifle does limit your defenses.
      It seems that a lack of leadership is the biggest problem.
      On July 4, 1970 when serving in the navy we were called out to support marines 20 miles south of Da Nang. Arriving on station, neither of our two 5"-54" naval rifles would function.
      It was "embarrassing" being unable to assist the Marines. I was much less stressed out, than the Marines getting attacked. It took a little while before AF planes arrived and started dropping napalm and HE on the enemy forces. Without the ability to direct air power, the Marines would likely have been overrun.
      Technology can and will fail, right when you need it.

  • Cody Cody on Sep 20, 2014

    Sounds like we have a fire discipline problem here. Is this the return of the pray and spray doctrine? Firing your weapon at an unsustainable rate is begging for problems. Oh, so what are you supposed to do when your combat load of ammo is expended? Blame it on the tiny 30 round magazines?