My gosh, does the Army seem to hate the M4 and M16 series of rifles. That’s hyperbolic, but when you look at all the programs they’ve utilized to try and replace the ubiquitous American service rifle, it’s tough not to think there’s some spite involved.
You could argue that the Army was trying to replace the M16 almost as soon as it was adopted. Admittedly, the switch to a rifle chambered in 5.56 was controversial at the time, but one would expect that the most popular rifle platform in America would have entered service with a bit more aplomb.
Today, some iteration of the M16 has been in service for nearly half a century and it’s proven itself in combat time and time again. In the 60+ years since it was originally designed, the weapon has seen multiple updates and new iterations, but is it really capable of sustaining America’s combat needs in a new era of great power competition? In order to answer that, let’s explore all the times the Army wanted to replace the M4 and M16… and why they ultimately didn’t.
The M4 and M16 Replacements
In 1963, the same man who invented the AR-15 turned M16 also invented the Stoner 63. I love the Stoner 63, and Eugene Stoner was clearly working with an idea that was well ahead of its time. The Army also saw the potential of this rifle, and began testing the Stoner 63 as a possible option for Army and Marine Corps small arms use. The M16 was still going through the adoption process at the time, and already, the Army was looking elsewhere.
Okay, so this wasn’t intended as a direct replacement for the M16, but Army’s interest a year before the M16 officially entered service was telling. The modular design of the Stoner 63 allowed a single receiver to be a rifle, a carbine, a belt-fed machine gun, an automatic rifle, a crew-served gun, and more. It could be both an M4 or M16, a SAW or a turret gun–really anything the warfighter needed.
The premise is fascinating enough that it may warrant its own article. Sadly, however, the Stoner 63 was a bit finicky and just couldn’t keep up with the M16, dooming it the discard pile.
Project NIBLICK was a follow-up to Project SALVO, which began in 1951 and ended with the suggestion to adopt the M16. NIBLICK was to be a grenade launcher that would attach to a Project SALVO’s unusual flechette-firing weapon. A flechette is a pointed steel projectile with a vaned tail to provide stability during flight.
This setup would have coupled SALVO’s rifle with the grenade launcher in an over/under design. At the time, the grenadier of an Army squad carried an M79 single-shot grenade launcher.
The rate of fire offered by the NIBLICK could be as high as 2,400 rounds per minute. That’s absurdly fast for a rifle. The M16 fires at only 700-900 rounds per minute, as a comparison. The program died due to issues largely related to the flechette ammunition, but we did gain the idea of an under-barrel grenade launcher
Advanced Combat Rifle
The Advanced Combat Rifle (ACR) program started in 1986, with the intention of replacing the M16, as the M4 had yet to manifest. Not just set on becoming America’s next service rifle of choice, the program aimed to double the hit probability of a soldier in the fight. Colt, HK, AAI, and Steyr produced samples that were all very interesting in design and execution. The ammo types involved flechettes, duplex ammunition, and caseless ammunition. Each was meant to increase the lethality of the soldier via a high rate of fire, higher capacity weapons, or duplex rounds that packed two projectiles into a single cartridge.
The ACR project proved unsuccessful, despite costing the taxpayer some $300 million dollars. Imagine how much training the same $300 million could have funded… More training might not have doubled a soldier’s hit potential, but it’d get them closer with an M4 or M16 than any of the platforms in this project could manage.
The Objective Individual Combat Weapon hoped to be the future of combat rifles. It was going to change warfare as we knew it! I know because I used it a lot in Ghost Recon back in the day.
Tom Clancy jokes aside, the OICW program actually had a lot of potential, and the weapon it produced brought a number of strengths to the table. Simply put, the OICW would grant soldiers the ability to kill an enemy while they hid behind cover with airburst munitions. It also would have replaced the M4, the M16, and the M249 light machine gun.
The OICW was really a combination of a light grenade launcher and a rifle. The grenades could be programmed to explode in the air as they passed the enemy’s cover, using fragmentation to kill them. The rifle portion would act as the close-range fighting tool. The weapons entered for consideration, but cool as they may have been, they were also huge, somewhat unreliable, and quite expensive. The OICW program did lead to some excellent designs we see today, like the MP7, the XM26, and the XM109. This concept may yet find a home in a future service rifle.
One such weapon that grew out of the OICW effort was the XM8. The XM8 was that rifle from every video game and sci-fi movie in the mid-2000s. Like so many others, this modernized weapon was eyed by the U.S. Army as a replacement for the M4 and M16 series of rifles. The idea was that the XM8 would be cheaper, lighter, and more effective than its predecessors. The XM8 promised modularity that allowed for an assault rifle, a DMR, a short carbine, and a light support weapon.
But as development carried on, the XM8 got heavier, more expensive, and wasn’t really any more efficient than the M16 rifle. The XM8 did see some success in the foreign markets, but never took off in the States.
The Latest M4 and M16 Killer – The Next Generation Squad Weapon
As I type this, the Army’s latest M4 and M16 killer is in development. The project aims to arm an entire squad of soldiers with a rifle and a squad support weapon, serving as a replacement for both the main infantry rifle and the M249 light machine gun. Weapons considered for the program also must utilize a 6.8mm projectile, rather than the now-classic NATO 5.56.
6.8 projectiles offer better ballistics than both the 5.6 and 7.62 rounds currently leveraged by American (and many international) service rifles. Sig Sauer, Textron, and General Dynamics have all submitted their final prototypes and truckloads of ammo to the Army for testing. Will it succeed? Maybe, but I wouldn’t put a bet down just yet.
Why do these efforts always fail?
A lot of these ideas might have been solid, but they came about before the technology of their day could support them. Also, the M4 and M16 family of rifles are downright outstanding. They’re lightweight, supermodular, and quite accurate as far as service rifles go. Rifles like the HK 416 might even be better… but are they substantially better? Is a rifle that’s 5% more accurate enough to justify replacing hundreds of thousands of service rifles and spending millions of dollars? That balance of cost versus improvement spells the end for many weapons programs.
Ultimately I think the swap from the AR family to something else will require a new caliber, and that caliber will have to provide a substantial improvement over the 5.56 round. As we’ve seen, the military needs short carbines for close quarter’s battles, long rifles for designated marksmen, and carbines for general infantry forces. The next gun will need to fit those roles and provide a marked increase in lethality to win over the bean counters.
The Army’s current program might be the answer, but that’ll be an uphill battle for sure. What do you think? Should we replace the M4 and M16? If not now, when and what would trigger a worthwhile change? Let me know below.
The Army Pentagon Brass believes the average Army infantryman is lazy and puny. That is why the Army brass is always looking to lighten the load for Army infantry even at the expense of choosing inferior lightweight gear to lighten their load.
Mitchell P Alexander says
The DOD has already accepted the 6mm ARC in June 2020, and this round is already fielded in the Middle East. It nearly matches exactly the ballistics of the .308 (plus some), with the form factor of the 5.56mm cartridge. Why not just retool with barrels and BCGs, saving the taxpayers a huge chunk ?
Mike H says
What wasn’t discussed and should be a focus here is the M4’s lack of reliability when exposed to sand. It’s built so tightly even a small amount of sand can lock it up and take it out of the fight. No, don’t tell me to clean it. I’m a gun-guy and cleaned my rifle like my life depended on it. We don’t get to choose the fight and our combat rifle needs to be ready to go in any environment. Laugh at the AK all you want, but if your rifle isn’t functioning, that AK has you beat. The direct gas impingement system of course makes this worse because it burns the lubrication out of the action and dirties up the weapon. Great ergonomics on the M4, but the overall rifle system gets a C grade. It works, but isn’t outstanding, especially compared to other rifles out there these days.
Rick A Dailey says
I understand the thought behind going to the 6.8mm round, but having a hard time figuring out why they have to re-invent the wheel with something besides the 6.8SPC when it is already in abundant production?
3rd Brigade says
Compact. Light weight. Lethality. Reliability. Accuracy. Magazine capacity. As a former grunt primarily concerned with either the Fulda Gap or the Iraqi menace I wanted all of the above and overall the M4 is a damned good weapon. But not perfect and its shortcomings may leave it behind in a future world demanding ability to take advantage of potential engagements at much longer than the traditional 200 meters or less yet being flexible (small enough) to be practical in tight city environments. And I never want to get into a situation where limited magazine capacity catch me changing mags as Abdul comes slavering out of a doorway 10 feet away waving a blazing AK all over the place.
I think all should have an eye on the Israelis and the bullpup. The added barrel length from the bullpup gives range and muzzle velocity traditional compact (re: short barrel) weapons like the M4 lack. The lethality issue is looming, too. The average raghead lacks body armor but we cannot plan our future on a single caliber of opponent. 1st world opponents in the next serious conflict may well have state-of-the-art armor and if we want weapons offering longevity to offset costs of the weapon we choose next it had better be able to penetrate what it hits. With new optics and mini-computers for individual weapons coming on line greater ranges will be normal. We should move up to something like a 6.8 with the plastic casings to obtain the weight savings of the new casings along with the improved performance of the 6.8 round. We might want to consider taking another look at 3 round burst options again, too. A target at 800 yards engaged by 3 rounds from a superburst…. Finally there is magazine capacity. Many issues have kept individual magazines below 30 rounds since WW2 but H&K and Calico both suggested helical magazines holding up to 100 rounds. A combination of encased plastic rounds, shorter than traditional rounds, would enable such magazines to hold 70 or so 6.8 rounds MORE THAN DOUBLING the present individual soldier’s engagement time before having to reload. Such firepower gives the individual soldier almost the capability of a squad automatic weapon. The compact nature of the helical magazines suggests a solder might be able to increase the number of rounds carried without incurring a weight penalty.
Don’t make the mistake of choosing one weapon over another; choose the features you want, reward each manufacturer for their creativity and engineering, and put all the best features into a single weapon. NOTE: Please include the equivalent of an M203. Not a 25 mm but the 40mm. The blast or shotgun effects of the weapon can determine an engagement; blowing down a key door, clearing a room, or engaging a vehicle. I always found a way to have a 203 and it proved itself on numerous occasions in a wide range of short range engagements when response time was NOW, not when arties or armor could intervene.
Michael Kincaid says
Hi! I am a Vietnam Vet and Worked Aircraft for 26 years until retirement and went to Gunsmith School at Yavapai College in Prescott Arizona and later came home and was lucky enough to be hired by the Air Force as an Armor / Small Arms Instructor since I held a Master Instructor rating while active duty. My point is I spent my time converting AR-15 Early rifles to M-16A2 rifles with kits provided for me and changing daily barrels on A2 rifles that shot erratic. Our students used jointed cleaning rods and cleaned either end and I thought about crown damage causing inaccuracies? I took 5 M-16A2 rifles with different throat readings and deformed crowns. I fired 5 shot groups myself off the bench of issue M-193 Ball 5 groups each. I am a Master Class High Power Shooter also so I can shoot a 5.56. I used a hand turned crown reaming tool and then retired each rifle same conditions and re crowing weapons allowed them to be put back in service without changing the barrel. In the Air Force we just replaced the barrel if an Instructor shot it and it was erratic. Simple gunsmithing saved us so much time and money! I received an award for my contribution . I wonder if and other branch did that? I was a Crew Chief while active duty and have some mechanical knowledge.
CRS, DrPH says
DANG! Great post, and excellent information!! The US military confuses me….we keep old platforms like B-52 Bomber going forever, but go back & forth on small arms. Your idea of repairing and upgrading issued rifles makes a lot of sense to me. Thanks for your service, Chuck!
Chuck West says
I think in this discussion we should look at the:
1) Reason we went to .223 (the original M-16 Cartridge) round for the M-16 and
2) The ballistic/striking energy improvement are we looking for
1. The M-16 was fielded as part of the “Tri-fecta” solution to the Chinese Human Wave Assaults we experienced in Korea (1951-1953 – China entered the war in Dec 1950). Along with the Claymore Mine and the M-60 machine gun, the M-16 gave the basic infrantryman double the number of rounds for the same weight of 30 cal ammunition they were carrying. The M-16 did have a reduced effective range compared to the M-14 chambered in 7.62 x 51, but the M-16 could still hit targets out to 400 meters, beyond which few infantrymen using iron sights could engage the enemy effectively. The problem at the time (circa 1960) was increasing the volume of fire in a US Army/Marine rifle platoon. I think history has shown that aside from a better sniper/DM rifle, we’ve equipped the basic rifle platoon with a capable weapon. The improvements over time (heavier barrel, forward assist device, re-working the round as the NATO 5.56mm with an improved barrel throat, improved propellant, armor piercing M885 projectiles, and M-1913 rails for universally mounting a variety of accessories) have steadily improved the rifle. The Marine M-27 or the H&K 416 with their gas piston action probably represents the zenith of the M-16 class rifle.
2. What improvements are we looking for ? I think the volume of fire problem has been solved. If we’re looking to increase accuracy of fire within 400 meters, I think the solution is to seek better sighting systems. For increased range, we could increase the round size to 6.8mm SPC, but then we’re staring to pay a weight penalty for the increased cartridge size (depending on which 5.56 round you choose, the 6.8 SPC round weighs approximately 40% more). The 6.8 SPC and the 5.56 M193 have very similar ballistic performance out to about 400 meters; past this distance the 6.8 performs better, retaining more velocity and energy. If the goal is to hit harder at longer distances, then the 6.8 SPC falls far short of the long range performance (retained velocity and energy) of the current 7.62 x 51 NATO round. I think the bottom line is: “What are we trying to improve?”
3. Summary: The 5.56 offers more rounds per pound than the 6.8 SPC, and gives the individual rifleman more rounds for the same load weight. The 6.8 shows improved ballistics and striking power at ranges past 400 meters, but then gives up the performance advantage to the 7.62 x 51 round at longer ranges (400+ meters).
It is important to remember that the latest greatest 6.8 ammo was seen as a solution to a problem. Chinese and Russian body armor now defeats 5.56. The ergonomics, optics, weight, modularity are carry over lessons from GWOT but 6.8 is looking into the future fight.
Americas’s strategy has been to equip a relatively small but professional army with leap ahead technology in order to gain overmatch on the battlefield
Brian Wilson says
In my view the NGSW risks shaping up to be the FB-111 of small arms – everything to everyman and ultimately not doing any of the intended roles to their potential. In the case of Sig Sauer, does Sig REALLY think NATO is going to adopt their Frankenstein round at a cost to NATO likely in the billions of dollars? Thats a lot of investment should the new tech not work out under real life conditions.
Any swap to a new cartridge needs to either use current cartridge technology providing for the least expensive option while providing for “the 80% solution” or have performance far exceeding current ballistics while IMPROVING a soldiers ability to hit at long distances under extreme stress to make the risk worthwhile.
Polymer cases? We are talking about GRAINS of weight differences between polymer and brass cases. It would be interesting to see some stats regarding the weight savings between brass and polymer cases. Back of the napkin calculations indicate that a 50% reduction in case weight in a 6.8 SPC brings about 2.5 lbs in savings for this loadout. Thats about 100 more rounds for the same weight but considering you will likely need more mags for the same number of rounds is the real estate there to carry it on a chest rig? I would also like to see the results of cold weather and desert testing with polymer cases.
Several companies have developed quick change barrel systems that work well. I personally have shot a Desert Tech rifle that was awesomely precise and had impressive POI consistency when taking the barrel off and putting it back on. This is a feature that should definitely be tested under harsh conditions as it would provide for flexibility for different missions with the same basic platform.
Even if the current options are not selected, if nothing else we will learn a lot for the system that eventually will be selected. If you don’t push the technological envelope, you don’t improve. Prototype “failures” still teach us a lot.
Great read on the militaries penchant for changing out the M4 & M16 but with the history both have had it would be difficult at best to replace them. I will be following you as I found your understanding of weapons most informative . Thank you for your service!
Kevin Colvard says
Great read, thanks for this! I will be following you now, what would be the best abenue to do this?