The primary issue with the new 6.8mm program and the original LSAT Caseless weapon program

 The primary issue with the new 6.8mm program and the original LSAT Caseless weapon program

A lot of questions have been asked on the new 6.8mm round the U.S. military adopted, and why it was willing to adopt a far heavier and higher recoiling weapon to replace the 5.56mm weapon; the reason why the program was implemented at all was because, originally, the new weapon was intended to be the same weight and have the same recoil. The United States military had successfully managed to produce such a weapon in the LSAT program, and only question came down to exact implementation of the rounds, which calibers would be chosen and which companies would produce the weapon. The entire program seemed to have been screwed up in execution, as the M7 is not a very well liked gun, particularly reliable or novel in design and is extremely heavy at nearly 12-13 pounds loaded, a lot heavier than the M4 carbine at 7.5 pounds. 

To explain the program as succinctly as possible, the 6.8mm program that produced the Sig .277 fury cartridge and M7 spear which has now been adopted by the U.S. military had it's origins in the LSAT program, or the Lightweight Small Arms Technologies program, which would later evolve in to the NGSW program. [1][2] The LSAT program managed to produce both caseless and polymer cased versions of the standard U.S. and NATO military 5.56mm and 7.62mm cartridges, as well as a rifle and machine gun in both calibers. A company called Textron managed to reproduce the G11's caseless propellant and produce very similar rounds in different calibers, utilizing lower temperature burning propellants with a much higher temperature resistance which were less likely to cook off or overheat the weapon, which was the key issue with caseless weapons previously. The company also managed to successfully produce functional and reliable weapons, that were said in testing to be more reliable than the guns they were intended to replace, particularly the M249 and AR-15. The weapons also had less felt recoil and were far lighter weight than what they were replacing.

Without a brass case, both of these new cartridges were approximately half the weight of what they intended to replace, with the 5.56mm variant being approximately 6.2 grams vs. 12.5 grams, and the 7.62 NATO rounds being approximately 13 grams vs. 25.5 grams for their previous brass cased versions. This would bring down the weight of a standard magazine  (30 rounds) from 1 pound to half a pound for 5.56mm, and from 1.3 pounds (20 rounds) to roughly .65 for the 7.62mm NATO. A standard soldiers combat load-out is typically between 210 and 300 rounds, or 7 to 10 magazines, and a soldier with the newer caseless rounds could now carry 420 to 600 rounds of ammunition for the same weight, or could carry ammunition such as the 7.62mm NATO that was twice as powerful. Of particular note, the 7.62mm variant when caseless ended up being almost identical to the 5.56mm's weight in brass cases, or, allowed a roughly identical amount of ammunition to be carried. The 7.62mm NATO is almost exactly twice as heavy as the 5.56mm, and by being caseless it halved the weight of the 7.62mm, allowing it to become almost exactly the same weight as the 5.56mm with a brass case.

The weapons themselves utilized a long action or constant recoil style of system, similar to a stoner 63, so it had very light felt recoil. A 10 pound gun, known as the LSAT machine gun, was capable of replicating the M249 at 17 pounds with less recoil and better controllability, while allowing a soldier to carry twice as many rounds, or shave off roughly 20-25 pounds off their carry load-out for the same load out of 1000 rounds instead (10 + 15-18 pounds vs. 17 + 30-33 pounds). The project was also able to develop a 14 pound 7.62mm NATO variant, that had very light felt recoil and good reliability, but allowed twice as much ammunition to be carried as an M240 machine gun. With the weapon being lighter than an M249 with the same weight ammunition, but having a round as powerful as the 7.62mm NATO, a question arises which is, is it possible to replace the 5.56mm soldiers currently use with a caseless 7.62mm round? Due to the weight of the gun, the ammunition, and it's recoil, it suddenly became possible for a 7.62mm rifle or machine gun to equal a 5.56mm rifle or machine gun in capabilities. You essentially could carry the exact same amount of ammo in an exact same sized gun that recoiled in the exact same way but with double the power and far greater range and armor penetration. 

In addition, for it's energy level the 7.62mm caliber has never been the most aerodynamically efficient design, or the best suited caliber for armor penetration. The same company also developed a 6.5mm variant, that was able to provide better performance than the 7.62mm NATO with approximately 1.5 to 2 times the sectional density, which translated to double the range and armor penetration for the same weight and size cartridge. It also has a much flatter trajectory, shorter time to target and is generally more accurate, being superior than the 7.62mm NATO sniper round in terms of ballistics, but for every round. The new meta basically became, if we can have a gun with all the same low weight, light recoil and high ammunition capacity as 5.56mm, with a round that is actually even longer range and more powerful than a 7.62mm NATO, why not adopt it? The project could also switch to polymer rounds by changing a single part, essentially a chamber which was not connected to the barrel, as the guns had a swinging chamber design which allowed for quick and easy caliber swapping and reduced temperature build up as it's swinging chamber helped to dump out heat and gas as well as improve airflow to the part of the gun that gets the hottest when firing, increasing it's temperature tolerance, a particular issue for caseless rounds.

The military found that polymer cases were better than brass cased rounds or steel for reducing heat build up as polymer is an insulator which absorbed the heat, while the caseless rounds were lighter. The polymer round were about 30% heavier than the caseless ammunition, but still much lighter than standard rifle cartridges they were intended to replace. The question of the program at this point became a matter of polymer vs. caseless rounds, with both being much lighter than what they intended to replace, weapons and ammunition, and with both being easily interchangeable by only swapping a few parts, in this case the swinging chamber, necessary due to the slightly different cartridge shape.

Choosing a single round for LSCO operations and thermal vision optics

Both as a desire to have a longer range weapon and a weapon that could pierce Russian and Chinese body armor while retaining the small size of the 5.56mm, more of an emphasis was placed on the 6.5mm or what would later be the 6.8mm version (which are only off by .004 inches, with the 6.5mm being a .264 inch caliber weapon and the 6.8mm being a .268, despite their nomenclature intended to make differentiating the two easy). The military wanted a smaller, lighter more compact weapon that would be useful for close quarters combat, but also be useful in LSCO or large scale combat operations against China or Russia. Essentially, to fight the Russians and Chinese, you would want a range advantage, as being able to shoot the enemy before they can get within range of you is a huge advantage, and this was an ability that was considered important in Afghanistan as well, which had mountainous terrain and open deserts where it was possible to see for miles in every direction. 

Particularly when fighting insurgents with a PKM, Dskha .50 cal or light mortars, it was useful to have a really long range weapon, but the weight and size of these weapons were often prohibitive for American use. If soldiers came under sniper or machine gun fire while using 5.56mm weapons, they could often be pinned down and have little ability to return fire, which lead to the adoption of heavier weapons such as adding marksmen to every squad with modernized M14's, such as the M14 EBR, and later on HK417's and other weapons. While a problem while fighting terrorists, it is also an even greater problem in LSCO operations, as unfairly matched battles are quite common. There is no rule in war that a soldier with a 5.56mm must go up against a similarly short ranged weapon, and so when facing an enemy with longer range weapons it quickly becomes a quagmire to stay pinned down until you can get some kind of angle on the enemy. However, in urban environments or trench warfare, a smaller weapon for maneuvering in close quarters is desired, and they are easier to handle in general, while the lighter ammunition of 5.56mm rounds means far more ammo can be carried. What these newer weapons offered was a weapon that was as light and small as a 5.56mm weapon, but with a caliber that not only met the capabilities of 7.62mm NATO, but greatly exceeded it. 

The United states military also worked on a .338 machine gun as well,  specifically to be able to match the effective range of a .50 cal, but be far lighter weight and smaller, so that it could be more easily carried on foot in the mountains. A key element that made longer ranges far more viable was the use of auto-aiming thermal vision optics, which made hitting targets at long range far more practical, especially moving targets like drones. With this new optic, the primary limitation to the weapon came down to ballistics, as in the capability of the round itself, and relied less on the marksmens ability such as in the past. A 25x zoom optic with the ability to see at night or in dark rooms, where all living creatures, vehicles and weapons glow like orbs from the background and that can automatically track targets and aim the gun for you really had the potential to change how we fought outright. The improvement in our soldiers accuracy via training, as well as better optics, meant we could really take advantage of these new weapons capabilities. Soldiers benefit from night vision and thermal vision in close quarters combat, as much as they do at long range, and thermal vision hosts a multitude of useful features like being able to see footprints, see heat signatures through camouflage, see through smoke and fog (allowing us to blind the enemy while we can see clearly), see as easily in the day as at night, and it gives the ability to autotrack targets with them standing out from the background. Thermal vision has also been used to spot landmines or IED's underground, as thermal vision can see a few feet underground and through thin walls and rooftops, allowing it to when adjusted properly see where the enemy might be hiding or where equipment might be concealed.

On top of this, mechanization has become a lot more common, so soldiers are within close range of a vehicle at all times that can store extra water, food, ammunition, and other supplies, further reducing how much weight soldiers need to carry in to combat. With that, heavier weapons and equipment or even potentially bringing two weapons with you becomes viable, as you can simply leave additional equipment in the vehicle if you don't need it rather than carry it on foot. If a soldier wanted to switch back to a substantially smaller 5.56mm weapon, they much more easily could with mechanization, and the potentially heavier weight of the newer weapon is fundamentally far less of an issue when extra equipment and ammunition can be carried by the vehicle instead. Thermal vision optics, mechanization and caseless/polymer ammunition allowed for essentially a new meta to emerge. Range can be taken advantage of, weight can be mitigated, and with better handling characteristics, there is a real option for heavier weapons to replace lighter one's if the right designs are used. 


Conclusion of the program and 6.8mm Fury (NGSW)
The conclusion of the program was that the focus should shift to a 6.8mm cartridge, leading to the NGSW or Next Generation Squad Weapon program. This was because the weapons and ammunition were the same size as the 5.56mm with the same recoil and handling characteristics, and due to the benefit of these weapons in large scale combat operations as well as against terrorists. The improved armor penetration and power was worth it when trying to defeat level III or level IV plates, which both the Russians and Chinese are using in increasing numbers, and in 20-30 years may be using a lot more commonly. Tangentially, as night vision becomes more common, thermal vision is easily able to replace it, being far more effective with far more features, and so it would behoove the U.S. to adopt thermal vision if only to maintain an edge over our enemies. The rounds and weapons also offered a significant improvement in performance for machine guns, particularly in regards to weight and recoil. 

Furthermore if the U.S. is going to replace the 7.62mm NATO and 7.62mm NATO weapons with a brand new cartridge and weapon anyways, why not use a 6.5mm or 6.8mm instead, which had far better ballistics for the same weight and energy. Once the program was completed, the military issued a new program to create an open competition for a new weapon using the 6.8mm cartridge's ballistics. Most the competitors chose polymer cases as it was easier for them to replicate this than caseless rounds, although the original company intended to allow the weapon to switch between both calibers by swapping out a few parts. So, the program was essentially based around a polymer or caseless 6.8mm round, with 6.8mm being chosen over 6.5mm due to the military's prior development of the .276 Pederson and 6.8mm Remington rounds. 

However, pretty much the entire purpose of the original program was shot down when sig's variant was chosen for some unknown reason, which lead to an 80,000 PSI bimetal case variant, that is exactly as heavy as the 7.62mm it intends to replace and has none of the recoil reduction or lower weight, except in the M250 light machine gun version, where they stole quite a bit from the original gun design (and the company sued SIG over this). The bullpup by comparison to the RM277, a competitor to both Textron and Sig, had very light felt recoil for a rifle of it's power and was lighter weight as well as more reliable than the M7, and it is kind of a wonder it wasn't chosen all things considered.  

It may seem weird to some, but the reason why the 6.8mm which is such a heavier caliber was chosen was due to the reduced recoil, lower weight of the weapon, and lower weight of the ammunition in the original program. It made sense to replace with the 5.56mm with something exactly the same weight as the 5.56mm but with double the energy and quadruple the armor penetration, but now that the sig was chosen it kind of flies in the face of the entire purpose of the program. Although all kinds of shenanigans can be considered such as Biden's administration disrupting the program or some kind of weird partiality to SIG given that literally all recent military small arms contracts have gone to them despite their less than stellar weapon designs (recent controversy with their pistols coming to mind after several people have been killed due to accidental misfires), it would make sense that, instead of adopting these bimetal cases that something like the RM277 or Textron's weapons be chosen, which can meet or exceed the requirements of the original concept. 

By no means is the SIG spear a bad weapon, and the M250 is particularly well liked. However, it's massive size at approximately 12-13 pounds and longer length than the M4 carbine make it difficult to see as a replacement for it. Further, the weight of the ammunition is twice as high, and hardly an effort was made to mitigate felt recoil. It would stand to reason that recoil mitigating weapons such as those developed by Textron or the General Dynamics RM277, which not only had far less recoil, but a lower weight, and shorter overall length, making it competitive with the M4 it was intended to replace. While bullpup weapons are generally shorter, lighter, and better balanced, overall a lot of options existed which were never taken advantage of. Even SIG seemed surprise it won the contract, and many of the arguments against the RM277 such as difficulty producing barrels in the polymer cased variants or caseless weapons, are criticisms that can be leveled at the 80,000 PSI bimetal case sig weapon. It seems almost ludicrous that the worst performing weapon was chosen that offered none of the weight saving advantages of the original program, and that once again the U.S. is out of a caseless or polymer cased weapon by weird shenanigans.