M2A1 .50 Cal: An Overview

The M2 .50 CAL has been the go-to weapon system in the Combat Arms arsenal since around the 1940s.  It is used in both offensive and defensive operations effectively against enemy combatants, light armored vehicles and even against low flying aircraft.

.50 CAL machine guns provide maneuver elements with heavy, effective direct and suppressive fires out to 1800m.  With its heavy rates of fire and long stand-off range capabilities, the .50 CAL is a favorite among all.  Its design has stood the test of time and for decades has hardly been modified…until now.

Soldiers across the Army are now receiving the M2A1 .50 CAL machine gun which will ultimately phase out the old M2 .50 CAL.  Why, you may ask?  The answer is simple, SET HEADSPACE & TIMING. 

To really understand why this is an important improvement, you have to first understand what the headspace and timing of a weapon is.  Most Soldiers take it for granted that they are able to grab a M240 barrel and slap it into the M240 and its ready to fire.

Many other Soldiers can pull out a headspace and timing gauge and set it for .50 CAL, but cannot tell you why they are doing it.  Very simply put, headspace is the distance measured from the part of the chamber that stops forward motion of the round to the face of the bolt.  Too little headspace and the round may not chamber correctly, too much headspace and the round may explode causing damage to the weapon and/or the shooter (I would suggest taking a look at a YouTube video of this…).

Timing, on the other hand, is the “timing” of the mechanical elements which fire the round.  Basically, as a machine goes through its cycle of fire a round is ejected and another moves into position to be chambered and fired.  Timing is ensuring that the round is properly seated before the firing pin strikes the primer.  Both of these elements are critical to ensuring safety when operating the weapon. 

As with most things in the Army, Soldiers become complacent and skip over proper procedures in an effort to be more expedient.  I have everything from guys assuming that the timing is always set in the middle of the thread so they don’t reset it or Soldiers just screwing in a barrel and backing it off 2-clicks and assuming their headspace is good.

I can’t tell you how many ranges I have been on and heard a .50 CAL fire irregularly, stutter and/or misfeed.  9 times out of 10, it is because the Soldier did not properly set their headspace and timing (or they did not put on any CLP).  Unfortunately for the Army, these practices have created a lot of risk and as a result quite a few injuries/casualties have been sustained. 

From a tactical standpoint, the .50 CAL gets hot laying down that heavy suppressive fire and barrels need to be swapped out throughout the fight.  In a combat situation, it is pretty difficult to pull out a headspace and timing gauge and conduct a proper headspace and timing for the .50 CAL.

Most likely, you’re going to assume that the headspace “click” count you had for the last barrel is the same for the replacement barrel and slap it on.  Again, a risky decision that is very unsafe. That all being said, the new M2A1 .50 CAL features a set headspace and timing which reduces the safety concerns both in the training and the operational environment.  Much like the M240, the barrels associated with each weapon have an established headspace and timing which allow for quick, safe barrel changes.

Some other nice features of the new M2A1 .50 CAL are the barrel handles.  I was never a fan of donning those goofy yellow oven mitts to take off a hot ass barrel.  The new M2A1 has a handle attached right to the barrel so easy on, easy off.

General Dynamics has also included a flash suppression device on the muzzle which aides in flash suppression during night operations (which is a great relief to those wearing NVDs).

So there you have it, the quick down and dirty overview of what’s new with the M2A1 .50 CAL.  Not much has changed, the M2A1 will still continue to be the heavy, reliable machine gun that Soldiers have come to rely on for years except now, the barrels are easier to change and no more headspace and timing!

chuck holmes

Chuck Holmes
Former Army Major (resigned)
Publisher, Part-Time-Commander.com
Email: mrchuckholmes@gmail.com

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4 thoughts on “M2A1 .50 Cal: An Overview”

  1. Seems like the M2 .50 CAL is blatantly inferior to the M2A1… Are they phasing out the M2 as of now? If they aren’t, they really should be. Having to check headspace and timing on each and every barrel change is too time consuming and ultimately dangerous to the Soldiers that have to do so, both because they’re vulnerable but also because improper work will cause explosions or misfires.

  2. Yes Justin, this was great information. I am glad designs have improved with headspace and timing. During a wartime situation, pulling out gauges can also create a dangerous situation. I also like the fact that you do not need to use oven mitts to change the barrel again. It is always good to see the Army making better designs on equipment creating a safer environment.

  3. Candace Ginestar

    Justin, what a great and informative article. Headspace and timing is extremely important and must be done right every time. I like that the new M2A1 takes the guesswork out of it, although I think understanding what headspace and timing is, is also important. Thanks for sharing.

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