If you had to ask me right now what thought the US armed forces should be using on the battlefield today, I would answer you with this:
This is a family of 5.85mm (.236") cartridges that, I believe, provide the answer to a long-attacked problem: logistics.
In the 1950s, the United States Army attempted to solve the problem of logistics in the military, as the post-WWII Army had, in service, 3 cartridges and four rifles, which greatly complicated getting ammunition to those who need it most.
What the US Army came up with was the 7.62 NATO, but as a universal round, it was a failure. It was heavy to carry for machine gunners, and was too powerful for lighter rifles and carbines to fire on full-auto.
In reaction, the Army later adopted to ultra-light 5.56x45mm NATO, also known as .223 Remington, which they continue to use today.
In the wake of the invasions of Afghanistan and Iraq, small lots of 5.56 were being delivered to special purpose rifleman in the field that could potentially change the way people think about small arms in particular.
This round was the Mk. 262 Mod. 0.
It featured the heaviest bullet the 5.56 could accommodate, a 77-grain open-tip match bullet with a super-thin jacket, and fired it at speeds matching that of the 7.62 NATO (which is slower than the previous 5.56x45 rounds). It was formerly believed that fragmentation could not occur for a military round at under about 2500 fps, which, for a round that relies heavily on fragmentation, as opposed to sheer bullet diameter, means that the round has to either have an enormous ballistic coefficient to hang on to every last foot-per-second of speed, or be going extremely fast to make sure that it has speed to burn. The Mk. 262 Mod. 0 changed that thinking.
The Mk. 262 showed that a bullet could be designed to fragment at velocities as low as 2000 feet per second, which meant that, with a properly designed bullet, the cartridge could be lightened, since the race-car like ballistics were not really needed anymore. Now, the 77-grain OTM bullet that the Mk. 262 fired did indeed have a superior ballistic coefficient, the best that an operational 5.56 can have. However, the ballistic coefficient, from a design perspective, is low, constrained by the overall length of the magwell of the AR-15 and the magnum-style case of the 5.56.
Using the lessons learned from the Mk. 262 Mod. 0 and discarding the 5.56 round entirely, I have come up with a cartridge system that effectively solved the logistics problem, increases terminal and other performance in nearly all areas, and reduces weight from other 5.56 replacement proposals by anywhere from 20-30%.
The cartridge comes in four "flavors":
M950 Ball: This is heavily based off of the Mk. 262 discoveries. Designed to perform against human targets, but also with barrier and vehicle penetration in mind, the M950 shoots a 105-grain, .236-caliber bullet at 2550 feet per second, using a modest pressure of 50KPSI, thanks to slow-burning powders. Ballistics are very similar to the larger 6.5 Grendel cartridge.
M955 Light Armor-Penetrating: This round is designed with barriers in mind. It fires a 97-grain, steel-cored projectile at 2600 feet per second. It mimics the capabilities of the M855 Green Tip round (while unconstrained by European preferences for "non-nasty" ammuntion), and it well-suited to SAW use due to its light weight and long range.
M956 LAP-Tracer: Similar to the M955, the M956 is a tracer round in addition to having some limited penetrating capability. Based on technology developed during the 6mm SAW ammunition program, its tracer can be seen out to 900 yards, further than both the 5.56 and 7.62 tracers.
M957 Dedicated DMR-Sniper; AP: The oddball of the M950 series, the M957 has a slightly elongated case (by 1mm) in order to prevent it from feeding into standard assault rifles and machine guns. In addition, it will not fit into the standard STANAG magazines of assault rifles, preventing cases of mistaken identity that could lead to possible deadly jams on the battlefield. For further safety, the round has a bright red band around the case neck, as well as a crimping in the neck, should the band wear off.
Why? The M957, due to its dedicated sniper role, operates at 10KPSI higher (60KPSI) than its standard companions. This allows it to send its 105-grain bullet--essentially a match version of the bullet used in the standard ball loading, with the addition of a tungsten penetrator--at up to 2750 f/s, giving it a range unequaled by rounds in the same class.
Sniper rifles that will feed M957 will also feed the other typed of ammunition as well, as it poses no long-term threat to the rifle's health. In addition, standard rifles and MGs will be proofed to withstand the pressures of this round, in the event that such a round does actually manage to be fed into one of them.
However, such pressures do no good for the standard action, and would wear them out quickly (especially MGs) if fed a steady diet of high-pressure ammunition.
In my opinion and research, a set of cartridges comparable to these would provide a true optimum for the modern warfighter, and would serve well in many respects for many years. Other cartridges that have been suggested for a full-out rifle replacement include essentially "Grendel-Magnums" that exceed the performance of that cartridge by usually less than 200 fps (and exceeding the OAL of the M16 by several millimeters). However, the Achilles heel of those rounds is that they weigh far more than the 5.56 NATO and even the 7.62x39mm, which is no lightweight. The M950 series of cartridges stay much closer to the 5.56 in terms of weight, being only slightly heavier. This cartridge accomplishes all the tasks that a modern military requires, all in the same four types of cartridge that have been with us for many, many years.
The decision to make the Sniper/DMR round a slightly different one originated with the realization that, due to special requirements by snipers, a single TYPE of cartridge could not possibly replace the standard set of four (ball, AP, tracer, match). The four types could possibly be reduced to three, but no less than that, as snipers have to have match ammunition and it is just not feasible from a production standpoint to issue every soldier match ammunition. In addition, the requirements for the sniper cartridge are the most onerous, requiring more range than is needed by any stretch of the imagination for an infantry rifle, and even a squad-level MG or SAW. Thus, since the sniper ammunition must be distinct anyway, I decided that a small augmentation of performance was in order, and that, as long as the high-pressure cartridges could not be used in the basic grunt's rifle, the Sniper/DMR load could be made to utilize higher pressures. Now, the STANAG magazines and infantry ammunition can all be used in the envisioned sniper rifle; the design would be such that they would be compatible. However, the dedicated sniper magazine, which is the only one capable of holding the M957 ammunition, could not be used in the standard rifle.
It is my hope that the ammunition types could be reduced to three: ball, AP/tracer and match, but I am just not certain that a 105-grain bullet could fit all of the components necessary to make it effective as both an AP an tracer round inside of it. Therefore, I created the M855 act-alike, the M955.
