Why do I get the feeling that the U.S. military will still use the M2 in most if not all HMG roles for xx years?

 

What's the big deal about weight? The vast majority of M2's are mounted on vehicles. Even a 50% reduction in weapon weight is inconsequential if you're mounting on a HUMVEE or M1A2.

BUT if you can get a .50 caliber weapon that weighs only marginally more than the M-240 you can give light infantry a portable, HMG.

You make a good point, but light infantry go to war carrying 60mm rounds or 81mm rounds, not just those weapon teams, so it becomes a balancing act, doesn't it...2-5Kg. of mortar ammunition or 2-5Kg of 12.7mm ammunition?  But I wouldn't dispute the weight issue...again though if it's not Airborne or Air Assault, but more "leg" light infantry then there is the HMMWV to carry a degree of ammunition and the weapon, but the 12.7mm is still man portable in a much lighter weight package.  Think of it as the water-cooled .30 caliber heavy machine in the Battalion Weapons Company, circa 1930-1953.

 The troops in the field like the M2 make a few improvements and put the things into production. Every article about the M2 is how they need a new gun and how much the troops like what they have.

As a helicopter combat aircrew I fly into "Indian territory" with 4 different pindle mounte weapons at various times, the M-60, the M-240, the M-2 and GAU-16, and my favorite (and most versitile) was the Ma Deuce. The only draw-back was if we went down we couldn't have been to take it with us like we can with the 60 or 240, thankfully the bad guys never got lucky and I didn't have to worry about it.

As a former grunt, I also have a certain affection for the Ma Duece, but my experiences have also made me cognizant of its shortcomings.  The fact that the M-2 .50 cal dates almost to WWI should not in and of itself be a determining factor as to whether or not the system should be replaced, but you have to take into consideration the technology of that era and how it might apply in the 21st century.  The achilles' heel of the Ma Duece, in my opinion, is the need for manually set headspace and timing.  I've boogered up the skin on my thumbs more than once trying to adjust the timing on an old and stubborn fifty cal.  A tool is provided to assist with setting the headspacing, but like anything else, that tool could be easily lost in a field environment.  Without proper headspace and timing settings the weapon may not work reliably, if it works at all, and on old and overworked guns the metal and internal will become fatigued to the point where the guns can no longer be coaxed into working reliably. 

 

Safety is another issue.  I can only imagine that a lot of modern safety officers have to turn their heads when they watch soldiers perform maintenance on the Ma Duece.  It is highly possible to injure or even kill yourself if you screw up while disassembling the M-2.  You can easily remove the back plate of the weapon while it's cocked and the guide rod is under pressure.  There's not much securing the guide rod to the receiver, and I've heard that if the guide rod jumps loose somehow it has enough pressure to penetrate a cinder block.  No commander wants to tell some mother than her son was killed while cleaning a weapon that was designed before her baby boy's grandfather was born. 

 

A few countries, such as Singapore and Belgium, have redesigned the Ma Duece to deal with the headspace and timing issues, but for some reason the United States didn't adopt these modifications.  Maybe instead of coming up with new weapons, they should give these foreign modifications another look. 

I think we can all agree that the M2 is a great weapon in a vehicle mount or defensive emplacement.   However, a light weight design could provide significant advantages in urban warfare, even if it required a 3 man team to haul the weapon, mount, and a reasonable amount of ammunition.

 

In areas such as the middle east where cement,, and brick are the most common building materials most buildings offer a significant degree of protection from 5.56mm and 7.62mm fire, but almost no protection from .50 cal firepower.  A .50 cal capable of be easily moved by infantry to covered positions or roof tops would be useful for taking out enemy blocking positions and sniper suppression.  Vehicle mounted weapons are frequently of limited usefulness in these roles because of the restrictions on movement in a city make them difficult to get into position or to vulnerable to counterattack.

Lots of buildings in the Middle East will easily shrug off .50 cal hits.  Or even 25mm cannon fire.

 

If the argument for a light infantry-friendly weapon to chew up strong-pointed opposition in an urban environment, I'd say the AT-4 or Carl Gustav is a much better choice than a .50 cal.

 

A .50 cal that is more easily man-portable (luggable?) into restricted terrain like up the sides of Afghan "hills" would provide some nice longer range direct firepower than just a 7.62x51 machinegun provides, however . . .

Any perception of the fractions of buildings in the Middle East that can shrug off 7.62mm and .50cal?

 

What about the outer walls that seem the alternative to fences over there?

 

And in urban combat, a stair well is restricted terrain.  What advantages would an easily deployed .50cal bring to the fight?

God yes...There was a great TV series running in Britain with a well known soap star doing an embedded reporter style tour with a regiment of British troops. In one scene they were following in after an air strike by AH-64s and the dished impact strikes from 30mm HEDP were visible, having made only a very passing dent in the thick clay walls of the village.

A soldier did turn in passing to the camera and said  "and these things can take out IFV's and tanks..."

My commanders when I was servicing always said "If it ain't broke, don't fix it." This issue of replacing the .50 cal sounds like yet another example of where our "best and the brightest" in our political and military have not figured this out yet.  

No idea on a % breakdown of which buildings/walls in the region will or won't take 50 cal hits, but know that larger shaped charges are considered a much safer bet for engaging buildings.

On the restricted terrain angle, I was mostly thinking of high ground (which could include building tops as well as hill and mountain tops, etc.) and then having a weapon up there that can reach out further than a 7.62x51 or x54 machinegun, and which can also do a better job of chewing up soft-skinned vehicles (trucks, etc).