Show the grenadier the expected point of impact and CEP radius on Google Earth

Friday, April 12th, 2019

Emeric Daniau summarizes the historical trends in individual weapons over the last century:

The rise and fall of the effective range of the individual weapon can be seen as a direct effect of the “competition” between infantry fire and artillery fire in producing battlefield casualties, and a compromise between the effective range and the practical rate of fire.

If in the 60 years before 1914, less than 10% of the battlefield casualties were produced by artillery fire, during (at least) the 60 years after 1914 artillery fire replaced long-range small-arms fire as the main casualty factor.

The need to continuously increase the volume of fire led to the reduction in the practical range of small-arms to less than 400 m, and allowed the rifleman to carry and fire more cartridges with his individual weapon.

During the same timescale, infantry fire changed from collective fire aimed at compact columns manoeuvring in the open, to individual fire aimed at a single fleeting target using the maximum concealment and cover.

Under these engagement conditions, the hit probability of infantry fire was found sufficient up to 100 yards, and very low at ranges longer than 300 yards.

In order to increase the efficiency of the infantryman’s individual fire at long range, the concept of “controlled pattern dispersion” (ideally, 5 shots in a diamond pattern) was first introduced but for proper execution needed to use a “low recoil” cartridge.

The adoption of the 5.56 mm in the M16A1 was seen as a first step in this direction, but battlefield experience revealed that the recoil of the 5.56 mm round was not low enough for achieving “controlled dispersion” at ranges higher than 50 m, and most western armies have recently come back to semiauto firing only. Further reduction of the recoil impulse (like the .17 SBR among other experimental diminutive cartridges) was not so successful due to the concomitant reduction of terminal effectiveness, the Russian 5.45 x 39 mm being probably the best balance of reduced recoil and useful lethality.

Up to now, it seems that the closest practical realisation of the concept of “controlled pattern dispersion” is the G11 “3 shot burst” free-recoil system (at 2200 rpm) and the AN-94 “accelerated double-tap” (2 shot burst at 1800 rpm), two systems that have not achieved wide acceptance due to the mechanical complexity involved and have yet to demonstrate tactical interest compared to semiauto firing.

During the ‘90s, medium-velocity grenades of limited diameter (20 mm – 35 mm) with “effective” ranges around 600 m, were seen as a way to compensate for the infantryman’s lack of accuracy at long range, but without a proper “all weather” Fire Control Module enabling a fast acquisition of the target (it is doubtful that any soldier will be willing to expose himself to enemy fire for more than ~2 seconds), the average miss distance of such medium-velocity grenades will remain much higher than their effective casualty radius and the improvement of the infantryman’s hit probability is open to question.

The current trend toward “medium velocity” 40 x 46 mm grenades is also open to question, because between 0 to 350 m (and particularly between 50 m and 150 m), medium velocity grenades will impact the ground at shallower angle than a low velocity round, increasing the fuse malfunction rate and also reducing the warhead effectiveness if the round actually detonates.

Anyway, shoulder launched grenades (low-velocity, medium velocity or rifle grenades) have a definitive place on the battlefield because they provide both additional capabilities (against defilade targets for example) and effective suppressive effects.

A few grenades exploding behind enemy lines is a known way to distract opponents firing at you, making them thinking that they are attacked on two sides, even with a miss distance between 20 m and 50 m. Of course, for this task there is no need for expensive programmable fuses and even more expensive FCM, a simple HE-FRAG or HEAT rifle grenade will do the job.

Additionally, with a simple 3-axis accelerometer and a GPS chipset (like those found in every smartphone) wired into the grenade-launcher, it’s probably easy to design a simple “indirect sight” that will show the grenadier the expected point of impact and CEP radius of its grenade on “Google Earth” (or  something similar), enabling this high trajectory weapon to be used without exposing the shooter to returning fire.

As a side note, readers should be interested to read that a “Mortar Ballistic Computer” is (or at least was) available for download on the App Store (designed for iPhone, compatible with iPad!)

Being involved more and more in “low intensity” conflicts (without HE support) or with restrictive Rules of Engagements (RoE) that severely limit the access to HE support, the infantryman needs to be able to engage opposing forces at longer ranges than previously thought (up to 600 m for point targets), and fix them or limit their mobility up to 800 m (area targets).

The debate over whether these engagement distances should be achieved by the Individual Weapon or left to “collective” weapons like the DMR and LMG is still open, but the weight and recoil of the 7.62 mm ammunition in its current incarnation militate against its use in a lightweight Individual Weapon, hence the mix of 5.56 mm and 7.62 mm weapons in the same fire team.


  1. Kirk says:

    I can’t quite put my finger on it, but there’s something that just feels wrong with the whole burst-fire solution to this issue. Especially when we start using itty-bitty projectiles not carrying enough velocity to be deadly, in service of reducing the amount of firer-caused dispersion.

    In my opinion, it isn’t correct to apply the lessons of crew-served weapons to individual ones, and that’s what we’re doing here. A crew-served solution is working within a team, is generally heavier, and is also usually mounted on a tripod or other support, firing at longer ranges than the quick snap-shot character of engagements with individual weapons.

    In other words, it’s apples to oranges, all over again.

    Sure, if all you’re worried about is hits generated, that’s all well and good. I’m not concerned about that metric, if the hits aren’t also inclusive of that little feature we term “stops”. That’s the essential problem with the XM-25 and other itty-bitty grenade launchers–The fusing and other things necessary to be in those warheads militate against enough payload to be deadly enough to be worth the while. The initial 20mm grenade fragments from the XM-25 were small enough and had such little energy that they were almost mere nuisances–They didn’t produce sure kills, which was what the guy firing it needed.

    I’m not saying to go back to a full-house horse killer like the .30-06 (which was really the genesis of that round–It had to be lethal enough to take down cavalry mounts), but I am saying that the characteristics which make a good crew-served solution may not be the ones we need at the individual level. If you restrict me to something tiny and less-than-fully-lethal in service of reducing recoil to the point where it can be fired in hyper-burst mode to enhance hit probabilities, well… I’m not sure that is a really good idea. At all.

    I think the Soviet/Russian mindless pursuit of the hyper-burst stuff, as typified by the AN-94, is really missing the point for individual weapons. As the US has found, you rarely really need even standard full-auto in an individual weapon, and when you do need it, the accuracy of it is secondary to the other effects you’re generating by going there. Except for those specific situations, carefully aimed semi-auto is much better, especially in scenarios where you’re having to follow a really restrictive ROE. If you’re a Russian, ROE doesn’t matter, ‘cos ain’t nobody gonna be calling you on collateral damage. If you’re US/UK, well… You’re gonna get called on it, big-time, and probably go to the ICC. So, for the US/UK, hyper-burst is a wasted effort anyway.

    I think the whole “thing” surrounding what we’re equipping the combatants with needs to be looked at from first principles on up. The role and purpose of individual weapons needs to be re-examined, as well as the mix of crew-served weapons.

    I’m almost of a mind that the individual soldier needs to be carrying a weapon that is less an offensive tool than a node in the communications network for spotting, identifying, and cuing targets for other weapons. Self-defense, and the occasional identified point target for the weapon component is about all we need to worry about, and the bigger piece is enabling all the other bits, like cross-talk between squad/section members and the higher authorities who authorize supporting fires.

    The biggest piece of improving this lethality thing, to my mind, is enhancing observation/communication and decision-making for all concerned parties. The weapons are almost secondary, to be quite honest.

    Consider the squad and platoon on the offense, in close-in terrain like a jungle: Individuals and teams move, but they cannot see each other, nor do they know where they are in relation to the enemy. Once an element has observed the enemy, they can’t easily communicate to their peers where they are, or that the enemy might in a position where another element might engage them without blasting the hell out of the original observer. The biggest gains in this idea of “lethality” are to be made with solving issues like this, and in making it possible for the leadership to grasp the details of the engagement, prioritize fires, and maneuver elements effectively.

    To be honest, I think that a properly networked and communicative team would be exponentially more effective even with obsolete weapons, than someone carrying the latest and greatest from HK, FN, or Colt. The weapons are almost a secondary concern, going forward.

  2. Kirk,

    I wish I knew enough about theory of warfare as you. I have enjoyed your commenting over the last few posts on infantry tactics. I only joined the Army out of need for finding my place after 9/11. I am out now, but you appear to know more than I ever did about warfare.

  3. Kirk says:

    Jeremy, I wish I were any kind of expert, but I’m just a guy who’s done a lot of reading, talked to a bunch of people, and done some thinking. I wouldn’t hold myself out as an expert in any way, shape, or form.

    I’d call myself a humble student than anything else, seeking understanding. There’s a lot out there I just don’t know, and I wouldn’t seek to put myself out there as “the guy”, because I know I’m ignorant of a lot of things that I’ve come to consider vital to understanding this stuff, and that a lot of what I think I have figured out might be wrong.

    Humility is what you learn after expounding on things you read from the “accepted experts” like Marshall, and then get slapped in the face by reality, as delivered by the men who were actually there. I’ve learned a bunch of that, the hard way. So… I’d hesitate to term myself any sort of “expert” on these issues.

  4. Lu An Li says:

    The Paris Gun, circa 1918. When firing at Paris the German had to take into consideration the rotation of the earth in the calculation of what trajectory to fire the high-altitude round to. A steer-able GPS round similar is available today. But do not forget the rotation of the earth.

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