I’ve got two firearms-related posts that have languished in the queue, one a review of a firearms catalog DVD, and this one a commentary on a monograph from Major Thomas P. Ehrhart of the Command and General Staff College entitled ‘Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer‘ (pdf) which is a very interesting document that casts new and interesting light on the near-eternal 5.56 caliber debate.

The abstract pretty much sums it up (dryly…):

Operations in Afghanistan frequently require United States ground forces to engage and destroy the enemy at ranges beyond 300 meters. These operations occur in rugged terrain and in situations where traditional supporting fires are limited due to range or risk of collateral damage. With these limitations, the infantry in Afghanistan require a precise, lethal fire capability that exists only in a properly trained and equipped infantryman. While the infantryman is ideally suited for combat in Afghanistan, his current weapons, doctrine, and marksmanship training do not provide a precise, lethal fire capability to 500 meters and are therefore inappropriate.

Comments from returning non-commissioned officers and officers reveal that about fifty percent of engagements occur past 300 meters. The enemy tactics are to engage United States forces from high ground with medium and heavy weapons, often including mortars, knowing that we are restricted by our equipment limitations and the inability of our overburdened soldiers to maneuver at elevations exceeding 6000 feet. Current equipment, training, and doctrine are optimized for engagements under 300 meters and on level terrain.

There are several ways to extend the lethality of the infantry. A more effective 5.56-mm bullet can be designed which provides enhanced terminal performance out to 500 meters. A better option to increase incapacitation is to adopt a larger caliber cartridge, which will function using components of the M16/M4. The 2006 study by the Joint Service Wound Ballistics – Integrated Product Team discovered that the ideal caliber seems to be between 6.5 and 7-mm. This was also the general conclusion of all military ballistics studies since the end of World War I.

The reorganization of the infantry squad in 1960 eliminated the M1D sniper rifle and resulted in the loss of the precision mid-range capability of the infantry squad. The modern solution to this problem is the squad designated marksman. The concept of the squad designated marksman is that a soldier receives the training necessary to engage targets beyond the 300-meter range limitation of current marksmanship programs, but below the 600 meter capability of actual snipers. As of June 2009, the equipment and training of the squad designated marksman has yet to be standardized. In field manual 3-22.9 there are only fourteen pages dedicated to training the squad designated marksman.

The introduction goes on:

Combat in Afghanistan has shown several trends. The enemy takes advantage of the terrain and engages patrols or convoys from high ground. He also combines this advantage with heavy weapons systems and mortars from a distance, typically beyond 300 meters.6 From the infantryman’s perspective, he attempts to fix the enemy, since his equipment limits his ability to maneuver, and attempts to kill the enemy through close air support (CAS), close combat attack, (CCA) or indirect fire.

The infantryman’s ability to fix or kill the enemy with organic weapon systems at distances beyond 200 meters is limited by his equipment and training. The incapacitation mechanism of small caliber bullets, such as the 5.56-mm, comes primarily from bullet fragmentation.7 Bullet fragmentation occurs only at a sufficiently high velocity. All 5.56-mm weapons are most effective when employed within 200 meters due to velocity limitations. Once contact is made, the fight is limited to machine gunners, mortars and designated marksmen. In the table of organization for a light infantry company8 only the six -M240B 7.62-mm machine guns, two- 60-mm mortars and nine designated marksman armed with either 7.62-mm M14 rifles or accurized 5.56-mm M16A4’s rifles are able to effectively engage the enemy. These weapons systems represent 19 percent of the company’s firepower. This means that 81 percent of the company has little effect on the fight. This is unacceptable.

If what the author suggests is accurate – that these issues and combat scenarios are prevalent in Afghanistan – this is a significant and immediate issue.

In lay terms, the problems are twofold.

One is equipment – the 5.56mm caliber M4 rifles that the typical soldier is armed with have an effective range between 150 – 200m, assuming they are using M855 ammunition (this is based on my ballistic tables for that round and a required terminal velocity of about 2500fps to achieve bullet fragmentation – otherwise it’s just a very fast .22). If his analysis is correct, and the typical engagement is beyond 300m, even longer barreled M15’s with higher muzzle velocity would be of limited effectiveness.

In addition, the typical optics for a M4 have a red dot that is 2 or 4 MOA (inches of displacement at 100 yards). At 300 yards, at best, the sights will make it more challenging to hit a 10″ circle (lethal zone for a person); the sights are optimized for quick sight picture at very close range.

The other issue is training and doctrine. Jeff Cooper said (in The Art of The Rifle):

The armed forces of today have almost abandoned the idea of serious riflecraft. There are many reasons for this, not the least of which is that rifle mastery is a demanding discipline and thus not really applicable to mass armies.

When Biggest Guy deployed, his platoon had one soldier with a M14 with a variable high-power scope (note that that soldier also had a M4 with a grenade launcher).

That’s a 7.62mm rifle that is potentially effective out to 1000 yards, and readily effective out to 600 – 700.

Here’s a picture of TG shooting mine:

(actually, I just like pictures of her shooting…)

The author makes two concrete suggestions.

One goes to doctrine and training:

The most immediate and cost effective improvements can be made through training and education. Soldiers and leaders need to understand the capabilities and limitations of their organic weapons. They need to understand what is required to maintain their weapons and keep them operational in all environments. This process begins in either basic training, or the basic officer leader course, and should continue through unit marksmanship programs. Equipment and organization need to be modernized.

The current 5.56-mm cartridge has limited application in open or mountainous terrain and should be improved, augmented, or replaced. A move to an intermediate caliber weapon or replacement upper receiver will increase the organic capability of the infantry squad and not substantially increase the soldiers load. By adopting an arms room concept, commanders will be able to choose the right equipment for the type of mission and terrain they face.9 Finally, doctrine should be reviewed and re-written to incorporate the capability to engage targets out to 500 meters. This doctrine should also include an updated qualification course, which more accurately simulates combat conditions and rewards shot placement. This type of course will give better feedback to the soldier and commander.

The other to equipment. He suggests that the military decide on and procure an ‘intermediate’ cartridge – the 6.5mm Grendel or 6.8mm SPC – and a supply up upper receivers and magazines to accommodate them, as well as improved optics – Trijicon ACOGs or Aimpoint with auxiliary magnification.

If you’re at all interested in this issue, this paper is a great read. Among many other things that I don’t touch on, it provides an excellent capsule history of military calibers.

I’ve not taken sides on the 5.56 squabble; but if in fact the engagements are frequently at 200 – 500m, we have to do something to increase the effective firepower of the troops.

For myself, knowing this, it makes me far happier to hear that Biggest Guy has graduated from a 5.56mm M249 SAW to a 7.62mm M240.
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