Replacing The M4

I have always had a special interest in the proceedings of small arms contracts within the U.S. Armed Forces. I’ve never served in the Armed Forces, but with the dream of becoming a firearms designer and manufacturer; it is extremely important to me to take into account what is happening in current conflicts to adjust to what is needed.

It should go without saying that the following thoughts are of civilian nature and is complete chairborne speculation.

Over the last month, we have seen numerous Requests for Proposal (RFPs) and contract solicitations for, what I would consider, “oddly” chambered small arms. These RFPs and contracts mainly cover the Army and Marine Corps branches, as well as U.S. Special Operations Command (SOCOM) units. Furthermore, whatever the Army does, the Air Force tends to follow with.

The U.S. Marine Corps (and SOCOM)

The Marine Corps and SOCOM are out to purchase some of the new General Dynamics Lightweight Medium Machine Guns (LWMMG) in .338 Norma Magnum. The capabilities in ballistics, range and weight of the platform exceed both .50-caliber and 7.62x51mm NATO. The Marines have already indicated that they wish to more heavily integrate the 5.56mm H&K M27 IAR into a marksman role, on top of the automatic rifleman role. For the Marine Corps, this is where the top-down approach comes into play.

The .338NM Lightweight Medium Machine-Gun.
The LWMMG is chambered in .338 Norma Magnum, again. This round is viable out to 1700-1900m and the platform is built like an up-gunned M240L that does as much damage as a .50 BMG, at those longer ranges. The LWMMG platform was designed firstly as an individual machine-gunner’s tool and it weighs-in at 24lbs unloaded. My thought process would be to replace most vehicle-mounted M2 Browning HMGs with the system. Then, restructure the two levels of infantry-borne machine-guns. The M249 SAW is all but on the way out of the Marine Corps. Thus, replace the remaining units with M240Ls: making them the new “Light Machine-Gun” tier. Furthermore, we already know that the Marines put out a Federal Acquisition Program that looks like a replacement of the M4 with the M27 to every rifleman. The FAR is for 11,000 rifles with associated equipment — click Revised Notice for PDF.

At this point, the Marines would have restructured every aspect of their infantry weapons. The M27 covers all roles as an Infantry Automatic Rifle, eliminating it as a special non-belt-fed “LMG” role and is also cross utilized as the designated marksman rifle (DMR). This would also eliminate the MK.12 SPR Mod. 0/1 from use.  An alternative to that route would be to replace all of those older 5.56mm DMRs with 7.62x51mm (or other) options that aren’t running on an M-16 DI gas system.

In a separate RFI, the Marines are also looking to go a similar route as the U.S. Army. Point #3 indicates that they are search for a new rifle that has the “ability to fire AB39 [7.62x51mm], .264 USA, .260 Remington, M80A1 [7.62x51mm], etc.” This is for the 2017 Marksmanship Technology Demonstration and not a whole lot else is known presently.

USSOCOM has the money to buy whatever they want. And, they do. So, they will. I care about their testing, not their deployed infantry weapon structure.

“Amateurs talk about tactics, but professionals study logistics.”
— Gen Robert H. Barrow, CMC of USMC (Ret.)

In the long run, you could potentially see a two-caliber logistics chain here — instead of the current three-caliber chain (5.56mm, 7.62x51mm and .50 BMG). Those two being whatever the Marines choose to replace the 5.56mm with and the .338 NM. The big what-if is what caliber the “lower-tier” 7.62x51mm MMGs and Designated Marksman Rifles gets replaced with. It could, theoretically swing to the Norma, and it could swing to the other replacement. Someone is going to demand to know about the monetary gains or windfall to be had here, and I agree with them in finding it out.

The U.S. Army

The first bit of note-worthy information was a short list of calibers in the 6.5mm bullet diameter range. The list was “.260 Remington, 6.5 Creedmoor, [and] .264 USA” plus a number of other unnamed calibers and these calibers showed up in numerous small arms proposals. Designated marksman platforms, LSAT Program moved up to 6.5 CT (Cased-Telescoped) from 5.56mm according to Kori Phillips,  and the Army is currently — specifically — looking for a whole new infantry rifle to replace the 5.56mm M4 carbine with. This includes a whole new caliber for the system.

I have a theory that we are about to see a total renewal of infantry platforms from the top, down. I am taking a wild guess that we will also see 5.56mm phased out. My prediction would probably take a several years to complete, but it is supposedly the perfect time for it. President Trump would be viewed as holding the cabinet that was extremely pro-military, in that case and in all likelihood.

U.S. Army Maj. Gen. Robert Scales, (Ret.), spoke to Senate Armed Services Committee — making a statement directly regarding the new rifle. Scales wants a new rifle within a year and he wants the specifications for the rifle program to be in the 2018 National Defense Authorization Act. He also offered specification requirements for the new platform, stating that it would be a simple “one-page” document;

“First, the rifle must be modular capable of being converted in the field to a carbine, rifle, machine gun or sniper rifle.

Second, it will fire an intermediate caliber bullet probably a military version of the venerable Remington 270.

Third, the rifle will be suppressed. A muzzle suppressor greatly reduces a rifle’s report and in the confusion of a close fight a quieter rifle gives a decided advantage.

Fourth, the new rifle will use a solid recoiling action like most first-rate assault rifles.

Fifth, the rifle should have a snap on digital sight capable of killing reliably to a range in excess of 1,000 meters.

Sixth, the rifle should be able to fire ammunition in a polymer casing. Polymer rounds weigh 30% less than brass cartridge casings.”

The Lightweight Small Arms Technologies (LSAT) Program on Ammunition Comparison.
As previously mentioned, this list corresponds with focuses on firearms technology within the LSAT Program, the suppressor testing in the Marine Corps, and the repeated statement of utilizing a 6.5mm caliber. The problem that I see with Scales is a previous statement, at the same Committee, regarding the M4 platform and the 5.56mm NATO. He heavily pushes a new round, while also stating that the M4 “operating system is fundamentally flawed”. The predictable question of “what do the operators use” came up from a senator. Scales, then, conceded that the HK416 “would be a suitable” alternative. The only thing that changes is the operating system of “another M4-style rifle”. He fell into the trap of that question, in my opinion.

The Ultimate Decision

As per most other, non-specialized military purchases, the U.S. Army will most likely be followed by the other branches. We saw this with the Modular Handgun Program — as every branch, aside from the Coast Guard, put in for purchasing information on the SIG-Sauer P320 (XM17 and XM18 handgun). The Army will ultimately get to the final stage of the individual rifle portion first. The ultimate decision boils down to which type of ammunition they chose for their platform to use.

By my stand-point, the choice is between brass-cased ammunition ( as we have it today) versus Cased-Telescoped ammunition. The LSAT Program has been an extreme success, on multiple fronts, since it’s inception as the Lightweight Machine Gun and Ammunition in 2004. Now, the program oversees three different calibers (minimum) for both rifles and belt-fed machine-guns, in two different cartridge technologies — Cased-Telescoped and Caseless. Textron’s AAI Corporation: Advanced Systems leads the front for the LSAT endeavor.

In the ammunition characteristics image above, you’ll see that logistics will stand firmly with the decision to pick Cased-Telescoped over conventional brass-cased cartridges. It’s lighter and likely costs significantly less to manufacture. Cased-Telescoped ammunition has been AAI’s crowning achievement in future ammunition types since, at least, 2008. AAI also has a rifle system that dispenses 6.5mm CT ammunition. The platform isn’t that much larger than a conventional M4 (Page-11), and it isn’t even optimized yet. There could be a lot more potential in the system.


U.S. Special Forces soldiers of Combined Joint Special Operations Task Force-Afghanistan provide security during the clearance of Mirza Kalay village, Mya Neshin district, Kandahar province, Afghanistan, March 8, 2014. USSF soldiers assisted commandos of the 3rd Special Operations Kandak in conducting the clearance to disrupt insurgents’ freedom of movement in the area. (U.S. Army Photo by Staff Sgt. Bertha A. Flores/ Released)
Another point is that, if you don’t go the route of a CT gun, you are looking at a rifle the size of the MK.17 SCAR-H, at the minimum. Interestingly enough, FN Herstal dropped .260 Remington caliber conversions for their MK.17 Heavy / MK.20 SSR at SOFIC this week. Officially, it will be because USSOCOM is searching for a new caliber for their Advanced Sniper Rifle Program (in .260 Rem., .264 USA, 6.5mm Creedmoor, etc…). Unofficially, it looks like everybody, and their brother in the Armed Forces, is preparing for a massive shift to a higher caliber. It continues to make sense that CT technology should be chosen, regardless if conversions for current platforms may be a better choice.

The Scales’ Points

Above, I went over the six points that Major Gen. Robert Scales pointed out in regards to what the Army needed in their next rifle. I’m going to go over these as shortly as possible.

  1. Modularity, convertibility and “in the field”. This brought back nightmares of the XM8 rifle system from the OICW Program (Increment 1). To me, modularity can potentially cost you in platform integrity. How reliable is this weapon system going to be while you want it to be an carbine, automatic rifle, LMG, and a “sniper rifle”? Depending on the system you want to talk about, most can only easily be converted to three of the four. Either Carb/AR/LMG or Carb/AR/DMR packages. The change is made either in barrel length or upper receiver swapping. In my mind, one should have dedicated systems for the role that you want them to play: a nonconvertible belt-fed, light machine-gun, for instance.
  2. The age old caliber argument. There are so many factors that come into play in a single caliber selection, let alone arguing pros and cons between two or more calibers. The U.S. Army, at the end of the day, is looking for a caliber that will deliver the damage of the 5.56mm with the immediate killing power. It’s been seen again and again, namely in Somalia and Iraq [Inside The Pentagon, “AAR”, 15 Dec. 2005], where 5.56mm ammunition wasn’t immediately killing unarmored combatants — regardless of the platform that was dispensing the mutual hatred. All I can say, the Army [and others] has learned from Afghanistan and determined they want more range and a better ballistic coefficient is needed for that. The argument will continue on long after 5.56mm is either retained or replaced.
  3. Putting suppressors on rifles is a given, but the Army would need to make sure that they aren’t losing ballistics in the particular suppressor they use. The Knight’s Armament NT-4 is the suppressor of choice by SOCOM and some conventional U.S. Military forces in their 5.56mm weapons presently.
  4. They want a piston-system. That’s also a given. You can Google all the rational for replacing a Direct Impingement platform. Wanat Province, Afghanistan, is just one example.
  5. I’m sure the complaint is about the current optics systems in use, because Picatinny rails are a thing. Current digital optic systems are rather bulky and mostly kept for use on DMR and sniper rifle platforms. Even the latest Ballistically Optimized Sniper Scope [BOSS], shown at SOFIC, is heavy. But, what are we looking for here? A fixed 4x like a modified Trijicon ACOG? Or, modify the 1.5-6x Elcan SpecterDR? For the projected caliber, is more power needed while retaining a Close-Quarters Combat, near-to-1x setting? They want range and CQC, but you have to be able to see for the former. I foresee standard ACOGs and Aimpoint CCOs being mounted on the new gun for awhile…
  6. Already covered. It’s a gimme for the LSAT program, which would cover a new rifle and light machine-gun with a 6.5mm CT caliber.

That should cover everything that I have been thinking about recently. It is interesting to watch the “stars align” for a 6.5mm cartridge across multiple branches.

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Header photo attribution: Oregon Army National Guard Sgt. Justin Sheffield, of Charlie Troop, 1st Squadron, 82nd Cavalry, 41st Infantry Brigade Combat Team, fires his M4 rifle while wearing a chemical protective mask during weapons qualification in preparation for deployment at the Orchard Combat Training Center, near Boise, Idaho, June 1. Approximately 190 Soldiers with the squadron will spend nine months performing security and support for military installations in Afghanistan. (Photo by Sgt. 1st Class April Davis, Oregon Military Department Public Affairs)

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