‘Black Rifles’ popular for a reason, with innovative technology

The black rifle is all the rage these days.
Eugene Stoner originally designed it for the 7.62x51mm U.S. military cartridge as the AR-10. It evolved into the AR-15 chambered in the new 5.56x45mm U.S. Military cartridge and adopted by the U.S. Air Force. The Army jumped on board and then designated it the M-16. That evolved into the M-16A1, M-16A2 and the current M-16A3/4.
The new military darling is the M4, the lighter, much shorter carbine version that evolved from the experimental XM-177 of the Vietnam War. The semi-auto version has always been known as the CAR, for Compact AR.
The M4 was designed specifically for tank crews. They have a real need for a lighter, but mostly shorter, rifle than the standard 39-inch-long M-16. Before the advent of the M4 in the ’90s the tank crews were still using .45 caliber submachine guns, the World War II “Grease Gun.” To say this arm was antiquated is an understatement, and the M4 was most definitely late to the game.
Being late, however, let the carbine evolve into something very sophisticated and free of the bugs that usually plague new systems.
The M4 was eventually to almost completely supplant the M-16 in combat use. The urban warfare we are engaged in now makes this compact rifle much easier to handle in confined spaces. The barrel is 5½ inches shorter and the butt stock is collapsible. Obviously, the shorter barrel makes the carbine more maneuverable in tight spaces like buildings and when being deployed from vehicles but maybe its biggest advantage is that aforementioned butt stock.
Most of these rifles have six positions that the butt can be locked into. This allows great versatility for the use of varying types, styles and thicknesses of body armor by our troops. It also allows the rifle to fit soldiers, sailors and Marines of a huge variety of heights and body types. The fixed butt has been rendered obsolete for a service rifle by the M4.
The new M4 also has a “flat top” upper receiver. This style is so much better than the old fixed carry handle that the U.S. military even updated the almost never-used M-16A3/4 to this configuration. The flat top has a Picatinny rail machined into the top of the receiver with multiple slots that allow the mounting of pretty much any optic made for firearms use.
The name comes from the Picatinny Arsenal, where the rail was developed; but in reality, it is just a slightly modified Weaver system that has been around for about 60 years. In point of fact, custom gunsmiths were milling off the carry handle of civilian AR-15s and screwing Weaver bases to the top for many years before the government jumped on board.
The new rifle did bring one problem to the forefront, however: stopping power. The current military service load for the 5.56mm NATO uses a 62-grain bullet with a steel penetrator in the tip and a lead base enclosed in a copper (or gilding metal) jacket. In the middle of the bullet is a cannelure, a smaller diameter portion that is knurled into the jacket. This serves two purposes: one is to allow the case mouth of the cartridge to be “rolled” into this minor groove so that the bullet doesn’t get pushed deeper into the casing upon being forced into the chamber. The other is to allow the bullet to break into two pieces upon encountering a “soft” target. This is phenomenal ammunition.
That break happens because the bullet is designed to “yaw” (rotate 90 degrees) when entering a soft target. When that yaw occurs, the bullet fractures at the cannelure because of the tremendous side-load of the bullet’s velocity and the resistance of the medium it’s traveling through. Those two halves then travel in separate paths as they continue onward. If a hard target is contacted, the lead base just pushes the steel tip through the obstacle until it runs out of velocity/energy. The hard target penetration is easily the equal of the vaunted 7.62 NATO (308 Winchester).
That is all great for our fighting men, but the problem is that it takes a certain amount of velocity for all of this to happen. The longer 20-inch barrel of the standard M-16A1/A3/4 lets this happen out to about 300-400 meters. The stubby 14½-inch barrel of the M-4 only gets out to about 200 meters before the velocity drops below what is necessary for bullet fracture. At the longer ranges it acts as a standard full-metal-jacket bullet and just bores a caliber-sized hole.
Most people, even educated shooters, think this is what FMJ bullets always do but they are mistaken. The 7.62mm NATO bullet also yaws but rarely breaks into multiple pieces. In reality, most long, pointed FMJ bullets yaw in soft targets.
Some even make a complete revolution and exit base first because they don’t fragment. The older versions of the 5.56 used in Vietnam had a 55-grain bullet of conventional FMJ construction that was barely stablized by its rifling pitch of one turn in 14 inches of travel. When this bullet contacted virtually anything in flight it tumbled and could cause major damage upon contacting and tumbling through a soft target.
It was so close to being de-stablized in flight that it was useless in arctic conditions. That’s why all U.S. Military arctic training and deployment was done with M-14 rifles until the M-16A2 and its one-in-seven-inches rifling rate came about, along with its 62-grain M855 cartridge.
There was one more great feature of the new M-4: It wasn’t plagued with the horrendously stupid three-shot-burst mechanism of the M-16A2. That allows the rifle to fire only a maximum of three rounds per trigger pull, intended to stop soldiers from “wasting ammo.” It’s about the stupidest thing that the military ever did to a small arm.
I would think emphasizing marksmanship, especially under stress, would be a lot more effective than a dumb three-shot burst “nanny.” I would think a soldier could also be gently reminded that they can only physically carry so much ammo and running out while being shot at is a bad idea. Alas, I believe the latest M-4s have this ridiculous appendage added to them now.
The “burst” model also upped the trigger pull to about eight-plus pounds of force required to fire the rifle. That is majorly counterproductive to marksmanship.
One other feature of the M-4 is apparently necessary but not conducive to accuracy. In order to allow the mounting of the M203 40mm Grenade Launcher to the new carbine, a deep groove had to be machined into the barrel just ahead of the gas block/front sight housing.
Rigidity of the barrel can only increase accuracy and machining a big groove around the barrel right in the middle is the wrong thing to do.
I believe they should have just made a larger forward ring mount for the 203 to retrofit onto M-4 barrels. The M-4, like all standard M-16 style service rifles, is capable of having the M-7 or M-9 bayonet attached. This weakening of the barrel could allow the barrel to be bent if the bayonet is used violently, but to be fair, I’m not sure when the last time was that a U.S. serviceman used a bayonet in combat.
I’ve mentioned all of this before, but many arm-chair commandos lament the loss of the M-14 with the adoption of the M-16. In reality, it was a wise move. The recoil is substantially less and much more ammo can be carried by the troops on patrol, almost three times as much by weight.
If the military would get back to marksmanship training and equip the M-16 family with a good trigger, the hit ratio would increase exponentially. Any combat soldier can fire an AR-15/M-16 with a good trigger extremely well if encouraged, instructed and educated properly.
Combined with the current military M855, or even better the Designated Marksman “Match” ammunition, the M-16 platform can take us well into the new century. The military has decided just that by declaring that there is no reason to adopt any of the new weapon systems anytime soon. There are special units deploying ACRs (advanced combat rifles) but their chance at widespread use anytime soon appears to be zero.
Personally, I have tried most of this new generation of rifles and they are just bigger, bulkier and more complicated. Some are just downright ugly! I would take an M-16 style rifle over any of them.
Surprising to many, the “AR” is about 65 years old, older than almost everyone reading this, and it is still going strong. It is our longest-serving service rifle of all time, by a large margin, and every year it just increases that lead.
Almost every other country in the entire world has adopted the cartridge of the M-16, if not the entire M-16 itself, and those that haven’t basically copied it.
For a rifle that so many people supposedly hate, it has completely dominated the world. I am happy to be a fan and user of the “Black Rifle.”
I’m even prouder to be a citizen of the country that designed, adopted and fielded it with such success.
– Jeff Hutchins, owner and operator of Rangemaster Gunworks in Lebanon, writes regularly on firearms for Lebanon Local.