Mortars

81mm Mortar_Team_Fires_on_Afghan_Insurgents_MOD_45151891

A guest post from Jed

We have a lot of discussion of fire support for mobile (armoured, mechanised) infantry, and touched upon the same subject in the context of light infantry. A number of articles penned by TD, myself and others have generated comments that examined one aspect or another of various elements of direct and indirect fire support:

My constantly re-stated preference for turreted, breech-loading, smoothbore 120mm mortars led one fellow commentator to suggest I may be a shill for a mortar company! I am not, I assure you my dear readers, involved in the arms industry at all, just an ex-Matelot, ex-Squaddie, professional IT geek, who has an opinion on everything………

So, I thought I would write a little piece to provoke some more discussion (because you all require SOOO much provoking….) around the subject of Mortars, aka “lightweight tube, HE, for the dispensing of.

History

So, Mortars have been with us for a surprisingly long time, I am not going to do any of the histories, you can all go and read Wikipedia for yourselves: http://en.wikipedia.org/wiki/Mortar_(weapon)

Modern British Army

The modern L16A1 81mm mortar (UK MoD equipment page), originally a product of Royal Ordnance (but now BAe) is one of those surprising little export successes. Incrementally improved, with advances including lighter weight tripods and baseplates, the wonders of modern IT applied to targeting, and lethal improvements to ammunition; such as notched steel wire wound around the inside of a thinner case for more shrapnel, and air-bursting proximity fuses, the good old 81mm remains a mainstay of infantry firepower at the battalion level, and nobody seems to have a bad thing at all to say about it!

You could perhaps be a little critical of our TOE and the way we have designed our structures for employing it. For example, we never got round to developing a mortar carrying variant of the Warrior family, instead of relying on ancient FV432 series vehicles, utilizing the standard hand-laid, and hand loaded 81mm firing through the open roof hatches. Also our employment of 6 mortars per battalion in “peacetime” to be raised to a “wartime” establishment of 9 tubes – by adding TA augmentees (or more likely stealing bodies from another battalion in the “less than all-out war” scenarios of the last decade). Contrast this to the “standard establishment” of 10 tubes of a US Army Stryker Brigade – but more on that later.

At the platoon level, we used to issue the L9A1 51mm handheld mortar, a weapon of a type often referred to as “Commando” mortars. As you all probably know, apparently our involvement in the Global War on Terror used up our stocks of 51mm ammo rather faster than had ever been planned, and then we found out there was no economical way to acquire more. This, alongside a long-held desire by some within the infantry establishment who were envious of the US M203 under-barrel grenade launcher, to see such weapons deployed widely, eventually saw the official replacement of the 51mm platoon mortar with up to two 40mm UBGL per section. Of course, the 51mm had greater reach than the 40mm, it made a bigger bang, its illumination rounds produced more light, and its smoke rounds burned for longer, making more smoke, etc etc I have no issue with this, different tools for different jobs. New model 40mm grenades (medium velocity) have increased range and increased bang, but they are still really direct-fire weapons, not suited to ballistic-ally lobbed, in-direct fire.

However, as it ever does, the cyclical nature of wars and technology made sure that what went around came around, and the UK issued a UOR for lightweight 60mm mortars. My understanding of this, and I could be wrong here, is that we first went out for such kit for limited special forces use, and then broadened the procurement to what in effect was a direct replacement for the 51mm as a platoon level weapon for use by non-SF troops in Afghanistan.

So now we have 40mm UBGL’s, 40mm AGL/GMG, Hirtenberger M6-640 60mm mortars, and 81mm mortars – surely our infantry have enough “fire support tools” at their disposal (we are not even touching on “rockets”).

Well before we go there, let’s examine the start of the art; see what we don’t have, and what others are doing.

The modern state of the art

First a caveat, I am not going to examine, mention the often exotic world of Soviet / Russian mortars, with big calibres, automated systems etc. I am going to stick to the “western” worlds systems and developments.

I am also not going to put much emphasis on our humble, beloved 81mm – I will mention developments in the calibre where necessary, but would like to focus on the latest developments at the lower end (60mm) and with its big brother (120mm).

The modern 60mm families

There are many 60mm systems, and families of systems to choose from:

  • Israel’s Soltam – the design chosen to become the US Army M224
  • Denel – the South African manufacturer of various mortars
  • Hirtenberger – the previously unknown (to me) supplier of the UK’s 60mm systems.

The 60mm mortar has recently become an extremely versatile weapon system, building upon the simplicity of operation of predecessors such as the UK’s 51mm and its WWII predecessors; while at the same time taking great advantage of lightweight materials, improvements in fire direction and targeting and the lethality of munitions. Different nations use many different bits of kit for fire direction and targeting, but at the lowest end of the scale, the Commando variant 60mm is handheld and aimed by eye for direct or indirect fire at what can be very short ranges:

At the other end of the scale Denel’s new long barrelled M6, firing special long-range ammunition can reach out almost as far as it’s traditional 81mm bigger brothers, and thus benefits from all the modern battlefield C3 systems, from handheld laser rangefinders for the Mortar Fire Controller (MFC) to handheld ballistic computers.

Munitions range from the staple HE, IR screening smoke, White and Red Phosphorous smoke/incendiary, white light and IR illuminating rounds, with various companies claiming their modern 60mm rounds have the destructive potential of the 81mm rounds of ten years ago (or less).

The family of systems approach makes good use of such commonalities while levering the technology. Denel for instance can provide the M4 short-barrelled, handheld “Commando” or “Patrol” mortar, “standard” barrel lengths for tripod-mounted “platoon” mortars, and even long-barrelled variants (as mentioned above) that might replace 81mm tubes at the battalion level. All can fire the same basic ammunition, with the sub-set of special long-range rounds required only to make the most out of the long-barrelled variants. Add in the latest M10-BLLR breach loading variant based on the M6 long-range, and you have a turreted weapon for direct or indirect fire support from afvs!!!   TDS even have a new “aiming” platform for rocket launchers and mortars, called Scorpion, which means you could have an automatically laid long-range 60mm mortar on the back of something like a Foxhound WMIK ……. just saying…….

As a doctrinal compare and contrast, the US Army puts it’s 60mm tubes in the battalion Mortar Company, alongside any other mortars of any other calibre, and detaches a two-tube ‘section’ to each of the 3 Rifle Companies. British practice with the 51mm was that it was carried by the Platoon HQ, giving a minimum of 3 per Rifle Company (with a fourth with the Coy HQ ?). Anecdotal evidence suggests the 51mm was utilised more for smoke and illumination than it was to make big bangs, but I can’t find any info anywhere on what the generally ammo scales were. The US M224 can be used handheld or with its base plate and tripod.

As an interesting aside, all versions of the Israeli Merkava MBT have a 60mm mortar as a ‘standard’ kit. MK1’s had this externally mounted, but all other versions have fitted to be loaded and fired from under armour. The Israeli’s picked up this habit from us – a 2-inch mortar was a standard fitting on the Centurion Mk3 we sold them!

Battalion Artillery – the 120mm Mortar

Although the British Army has never “gone big” many of our NATO allies have.

The 120mm mortar is perhaps seen as somewhat of a strange beast; too big to manpack (not that you really, really want to be man packing 81mm, but you can), not as long-ranged as the 105mm Light Gun, but lighter and easier to manoeuvre on a wheeled carriage or underslung from a helo. Modern technology has once again started to change the game here, with precision-guided rounds, cargo rounds, extended range rounds, and lightweight materials being applied to tripods, carriages etc. However, while it might be lighter and easier to lug around than a 105 for light infantry, it is really in the mechanised area where the 120mm has made large bounds in capability. There are so many variations on the theme, it is worth examining them in terms of a categorization of technological capability:

First, good old fashioned – a manually laid and manually loaded 120mm tube in the back of your favourite vehicle, e.g. the old M113 based system of the US Army, and the original version of the Stryker Mortar Carrier Vehicle (MCV-A). 

Second, automatically directed – an automatically laid, but the manually loaded system is now the standard for the US Army Stryker brigades (MCV-B) and Heavy Brigades (M113) uses the standard 120mm tube on the CARDOM platform provided by Israel’s Soltam. The platform is connected to the fire control system and automatically “lays” the mortar as required to achieve the firing solution as soon as the vehicle comes to a stop. 

Third, automatic loading – the Singapore Technologies SRAM (Super Rapid Automatic Mortar) system is a good example. Fitted to anything from the rear module of a Bronco (Warthog AATV) to a HUMVEE or even their own “Fast Attack” lightweight 4 x 4, the SRAM is a recoiling mortar with an automated arm loading the bomb into the tube.

Fourth, best of both worlds – Auto laid and auto loaded – this was the goal of the USMC Dragon Fire Expeditionary Fire Support System (EFSS) – which unfortunately did not quite come to pass – yet. The European TDA 120mm rifled mortar, on a platform like the CARDOM which automatically aims the weapon, while also having an auto-loader function like the SRAM. The EFSS would be fitted in armoured vehicles (LAV) and on a trailer for towing.

Instead, the Marines have deployed a towed trailer-based system, which with a “prime mover” Jeep type vehicle small enough to fit inside a V22 is manually laid and loaded

Fifth, turreted Breach Loading – ahhhhh’ soooo much flexible fire support goodness! But again, so many options to choose from for your direct and indirect fire support requirements, depending upon the state of your bank balance:

Fifth and a bit. Manual turreted – the BAe Advanced Mortar System (AMS) and AMS II are good examples. Fitted in a manned turret and operated by a crew as any other breach loading tank gun. Tested on the Warrior and used in service on the GM LAV wheeled AFV by the Saudi National Guard

Finally,  automatic turreted – say “Ahhh, Patria” – it rhymes! From the twin-gun goodness of the AMOS to the much smaller and lighter weight fully automated death-dealing goodness of the NEMO, the Finns’ have you covered! I like that Sven Ortman when he stops by always worries about the rate at which the AMOS will fire all its rounds, so don’t forget to buy a second, identical armoured vehicle of your choice to use as an accompanying ammo resupply vehicle if you pick this puppy! To be honest, a high rate of fire with simultaneous rounds impacting on target at the same time might just bump such a system from being the infantry pocket artillery to be a “close support” element of the actual Artillery :-)

So, if you want to join the big boys and go up to 120mm there are options, from an infantry mortar in the back of an FV432 that used to carry an 81, to put a manually operated turret on a refurbished Warrior, to buying a FRES SV variant with a NEMO turret – “you pays yer money and takes yer choice.”

Flexibility-guided and long-range rounds

As I noted, the 120mm mortar might be lighter and easier to cart around than a 105mm Light Gun, but it has a much shorter range. That differential is being eaten into a little by super-charge rounds, and even by rocket-assisted rounds. However, the advantage of the mortar in this respect is that it has a higher weight of HE than a 105 round (being closer apparently in effect to 152 or 155mm rounds) but also in the amount of money being invested by many parties – both users and suppliers, on applying new technologies to the humble mortar round.

The STRIX infra-red guided, top attack, anti-armour round has been available for a long time. It beat the British Merlin MMW radar guided 81mm round by actually making it into service. However, at the moment, developments appear to be moving down two well-trodden tracks: GPS and Lasers. The main obstacle to adding any kind of guidance electronics to a mortar shell in the past has not really been miniaturization, as you might think, but the G-shock hardening of components. With all solid-state micro-electronics, this appears to have been dealt with now. Another breakthrough has been in the aerodynamics and the electro-mechanical actuators to fit movable fins to the front end (the fuze or guidance section) of a mortar round to do the actual guidance of the flight path.

A GPS guided round can much improve the CEP of even a well surveyed and laid in mortar – and despite the reputation of being an ‘area’ effect weapon, mortars can be quite accurate. The GPS also allows for range extension, in that the flight reaches the topic of its ballistic arc, and then takes a non-conventional “gliding” flight path to its eventual destination. As you may not need such accuracy for every mission, the additional cost of a GPS enabled round should not be a big factor in any way.

Next up is the semi-active laser-guided developments underway. Based on the requirements of the COIN centric last decade of wars, with tough to meet Rules Of Engagement (ROE) the US and other nations have decided that a laser-guided round is a good idea for pinpoint accuracy while producing less collateral damage than even a Small Diameter Bomb (SDB) dropped from your personal favourite fast air platform. Such rounds are in testing, so expect to see them in a back of a Mortar carrier vehicle near you soon!  Actually, the potential issue with laser-guided rounds appears to be the paucity of laser designators available to illuminate potential targets. This might actually be less of a problem for armoured or mechanised formations, because again, with the miracles of modern miniaturization a laser designator able to “paint” a target out to 4km or more is no longer a “60lb Bergen” sized piece of kit, and should be added to recce vehicle turrets or RWS reasonably easily. Of course, nothing is that simple, as then we have to set the beam to the right Pulse Repetition Frequency (PRF) for the seeker in the weapon to find it etc, but despite the devil being in the details, laser guidance is being talked about for 81mm and even 60mm rounds!

As I have mentioned in numerous comment threads, the turreted 120mm mortar could even take on the anti-tank over-watch role, at a pinch, with the Israeli LAHAT laser-guided, top attack, dual warhead anti-tank missile, which was designed to be fired from smoothbore guns.

Mortar employment / deployment – Compare and Contrast

Just a quick compare and contrast exercise with our US allies. A Stryker Medium Brigade Combat Team (BCT) has 10 Stryker MCV-B, each equipped with the CARDOM 120mm mortar system. 6 are detached as two-vehicle sections to the Rifle Companies, 4 are kept at ‘Battalion” level. Although the vehicles are identical and all carry the same 120mm system, which cannot be dismounted from its mounting, the American mortar company takes the ‘arms locker’ (or armoury, or “golf bag”) approach – the 4 battalion level vehicles carry an 81mm mortar for dismounted ops, and the 6 company level vehicles carry the M224 60mm mortar. I have no idea as to the amounts of rounds of any specific calibre that are carried per vehicle as standard, or what this means for their logistical support in general but it is an interesting approach.

In a similar manner I have recently read that Canadian Army artillery troops are going to be trained on the M777 155mm howitzer, the 105mm Light Gun and the 81mm mortar, and will deploy with the appropriate system as required (we do something similar with cross-training on AS90 and 105mm LG).

Summary

Is the solid old 81mm being left behind as a soon to be ‘red-haired stepchild’ ?

Could a “family” of 60mm mortars, with handheld Commando mortars in the Platoon HQ and long-barrelled, long-range 60mm versions being used at the battalion level replace the ‘81’ for light infantry formations?

Could the heavier 120mm mortars in some form replace the 81mm for mechanised and armoured formations?

A modest proposal, or two, or three……..

So to provoke the discussion I will make a few modest proposals, I don’t care about budgets really, this is heading into fantasy fleet land somewhat, as I said mainly to provoke discussion in the comments thread

  1. 120mm turreted mortar becomes standard for Mechanised / Armoured Infantry formations and is added to Brigade Recce Regiments (ex-FRR). Let’s go with BAe AMS II turret on Warrior and FRES platforms.
  2. 60mm mortar becomes standard for non-mechanised infantry; with a handheld Commando mortar in the Platoon HQ, and the long-barrelled, long-range variety in the weapons/support coy.
  3. Marines get SRAM for Viking in the Armoured Support Group. 29 Cdo Rgt RA gets 120mm on wheeled carriages or on BAe trailer mount for close support fires.
  4. 16 AAB gets an Armoured Support Group with all the Warthogs, which also gets an SRAM variant. 7 RHA also gets 120mm in place of 105 LG.
  5. TA get all 81mm, and eventually make the slow transition to 60mm, same as regs.
  6. FRES SV “Protected Mobility” variant gets Israeli style “under armour” 60mm
  7. Scimitar MK2 gets accepted into core fleet as a specialist light armoured fire support vehicle with Rarden replaced with Denel M10 (or just gets the Denel turret with it in).
  8. 1 x RA regiment re-roled to “Armoured Close Support” with 4 batteries of 8 x FRES SV with AMOS turret (paired with FRES SV Ammo tender), batteries on 1 in 4 roulement (training, high readiness, deployed, re-set).
  9. 105mm Light Gun retired (consider this in the light of more mortars, a wheeled 155mm, AS90 all to TA and LIMAWS(M) revived for “long-range sniper” role with GMLRS).

I am sure there is enough contentious claptrap there to get you all talking!

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