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Author Topic: Mortars as anti-tank weapons?  (Read 15904 times)

Offline Charles Gray

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Mortars as anti-tank weapons?
« on: March 22, 2010, 02:59:19 am »
In ARMOR magazine, there was one idea for the use of a lightweight armored vehicle using a heavy 120mm breechloading mortar firing guided rounds as an "Indirect" anti-tank system.  Ideally, you would be able to use it both for anti-tank indirectly and more general support of infantray.

 So my question is this-- could a 120mm guided mortar round be powerful enough to give the kill probability to make such an indirect anti-tank system viable?

Offline Lauge

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Re: Mortars as anti-tank weapons?
« Reply #1 on: March 22, 2010, 03:18:28 am »
So my question is this-- could a 120mm guided mortar round be powerful enough to give the kill probability to make such an indirect anti-tank system viable?

A lot would depend on the attack profile.

Would the antitank mortar bomb (AMB), assumed to use a high-explosive anti-tank (HEAT) type warhead, be used in the direct-fire, flat trajectory mode against tank targets, or in the more typical-for-mortars high trajectory mode?

In the former case, a 120mm mortar shell would be little different in effect from a 120mm tank gun HEAT round. Iffy against the frontal armor of a modern tank.

In the latter case, the AMB would attack the thinner top armor of the tank, much like the STRIX from SAAB Bofors (http://www.saabgroup.com/en/ProductsServices/products_az.htm?url=http%3A//products.saabgroup.com/PDBWebNew/Generic.aspx%3FEntrance%3DProduct%26ProductId%3D658). This should give a good probability of a target defeat.

Another factor is that, since the AMB would be guided, it would probably be more expensive than a "dumb" 120mm tank gun HEAT round.

All in all, I see the AMB concept as giving existing (self-propelled or otherwise) mortars an anti-tank capability, not as a way forward to a primary antitank capability.

The vehicle itself would be something like the Russian 2S23 Nona (http://www.globalsecurity.org/military/world/russia/2s23.htm) or the Chinese PLL05 (http://www.sinodefence.com/army/artillery/pll05.asp).

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Offline TomS

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Re: Mortars as anti-tank weapons?
« Reply #2 on: March 22, 2010, 08:11:00 am »
The idea is not to use mortars as a unit's primary anti-tank capability, but rather to consider using heavy-caliber mortars instead of high-velocity tank guns as general purpose fire support for infantry units.  Consider the Mobile Gun System intended for US Stryker battalions.  Their primary missions are defeating bunkers and hardpoints, mouseholeing walls for infantry assaults, engaging light armor and soft-skin vehicles, killing infantry moving in the open, and so forth.  Defeating tanks is a decidedly secondary or even tertiary mission--the same units already have anti-tank capabilities from other assets. 

The proposal is that a heavy-caliber direct-fire mortar (like the Swedish AMOS or British AMS, for example) would be better than a tank gun for most of those missions.  It certainly carries a bigger HE charge, which would be better for knocking holes in walls and so forth and 120mm mortar rounds will thoroughly mess up light armor even on a near-miss.  The only area where the tank gun is clearly superior is in killing medium to heavy armor, and that's where guided anti-tank rounds would be needed.  As long as they could strike top armor, such rounds would absolutely overmatch existing tank armor (probably even better than 105mm APFSDS against tank frontal armor). 

There have been quite a number of guided mortar rounds for anti-tank use, though I can think of only one (Strix) that made it out of development.  They're not cheap, but they could b cost-effective if the accuracy is high enough.  Assuming laser or other suitable man-in-the-loop guidance, the potential for pinpoint precision makes them desirable even when anti-tank use is not required. 

Offline HeavyG

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Re: Mortars as anti-tank weapons?
« Reply #3 on: March 22, 2010, 10:22:24 am »
An anti-tank mortar round would also permit the vehicle firing the round to fire it behind cover and out of the line of fire of direct fire weapons, thanks to the mortar's high firing arc, compared to a regular tank gun's much shallower arc.

If I'm not mistaken, anti-tank mortar rounds were also developed for man portable mortars (around 81mm), so a mortar fire would have the same advantages as a mobile mortar (though with considerably less mobility).

Offline GLAR

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Re: Mortars as anti-tank weapons?
« Reply #4 on: March 22, 2010, 04:21:24 pm »
Yes, 120mm soft launch brilliant rounds-



Are superior to 120mm high velocity KEPs in the AT role for a number of reasons, mostly having to do with the weapon it is fired from:

1.  AMOS (twin barrel, auto breachloading turret) can be put on almost any chassis, including the M113, CV-90 and several Wheeled types.  Which means you can deploy it in less than 60 days.



2.  Rate Of Fire is vastly superior, on the order of 24 shots per minute to the steady 6-8 and surge speed 10-12 that an Abrams can put out.  Some MBT are better at ROF because they are autoloaded but even those rarely exceed 15spm.

3.  The Mortar has superior range.  On the order of 12-15km.  This is well beyond LOS in most conditions and allows the unit to fire indirectly in modes which the threat tank _cannot_ respond to without going indirect itself.  The latter options is not impossible, the M1 having gone through three iterations of XROD, STAFF, TERM and now MRM guided development programs, but the point is that it doesn't buy you anything because by the time the either round arrives both are defendable against with APS like the Arena and Trophy as well as advanced ERA like CACTUS.

4.  Soft launch is a lot less hard on the missiletronics.  Keeping in mind the 30,000G that the Copperhead endured.

5.   Tanks suck in a lot of important areas like mountains and swamps and narrow streets.  Iraq has seen a lot of Abrams end up spilled because they went down a soft dirt berm between two flood control areas and had the road collapse under their weight.  They routinely beat up tiny streets to the point where massive repair budget is (or was) allocated for NATO Germany.  And in AfG's 'hills' their typical 15-20` of barrel elevation vs. the 85` of the AMOS turret makes them useless against RCL and LAW as well as direct fire from the heights of surrounding ridges.  Indeed, their top armor and sighting systems are also exceptionally poor to the extent that a command is often reduced to opening his hatch to bullets coming in to find targets for his .50, even assuming he has electric drive to remote it.

6.  Gun shortcomings also applies to the way that ammunition is used.  Current tests with modernized beehive rounds like the XM1028-



Show the lethal downrange risks of firing this kind of ammo.  Similar problems exist with mixed sabot and heat rounds in that you will perforate several houses and collapse entire buildings respectively when firing at guerillas with the main tube.  Sometimes this is useful as it certainly teaches a lesson about lingering too long to ambush and snipe from behind our infantry.  More often than not, it is fly hunting with a sledgehammer.

OTOH, a 120mm mortar can theoretically do the same thing if it has a HESH or HEP head with a big enough bang in it.  But it can also be fire from a centralized location (i.e. never leaving the FOB) and still plunge vertically to hit just one intersection.  Covering multiple patrols.

7.  The 120mm usually has more and more diverse ammo.  Smoke, Illumination, AT, Frag, HE.  With various airburst and penetration fuzing options as well.  A typical NLS loadout (BAe's single barrel AMOS) is around 70-80 conventional rounds with another ten 'specials' in a side compartment.  This is compared to the 40-42 you can stuff in an Abrams.

http://www.globalsecurity.org/military/systems/ground/m1-specs.htm

http://www.thefreelibrary.com/Fast+moving+120mm+mortars:+the+120-mm+mortar+is+the+largest+indirect+...-a0171018005

Of course there are conditional modifiers here.  You don't really want the US Army solution of a 120mm breach loader in the back of a Stryker.  First, because the 120mm is so heavy they actually have a secondary 89mm (and ammo and training costs) to go mobile with.  Secondly because the days of open hull AFV should have ended with the gun carriers and halftracks of WWII.  If you tie into it with another artillery shooter, high angle threats (buildings and mountains again) or start to face top attack systems of any kind (an RPG against an adjoining wall, a rifle grenade from 400m, a handgrenade from 30, or an RBS-56/AT-14 Kornet from 1,500) you really don't want to be open airing it from even a near miss.  Under Armor is the way to go because it allows for faster onset of fires across 360` and more systems integration to properly place them while keeping the crew free from small arms risk if the weapon must be used essentially as an assault gun.  Which the TMS/AMOS can also achieve, out to about 1,200m or so.

CONCLUSION:
The fact of the matter is that tanks are dinosaurs.  They really should have been pulled from the front lines years ago but because they represent a technological 'epoch' they have a use in keeping the competition restrained to a specific class limitation of performance to which basic improvements in the three primes of protection, mobility and firepower render the system easy to upgrade.  There is also a considerable institutional inertia, at least in the U.S. Army center around heavy-tread systems.  What Shinseki I think it was did when he wanted to go to the wheeled 'light brigades' is threaten to make public an image of a LOSAT which, fired 8 at a time from a Hummer, went in the front grate and out the back engine grill of an M1A2.  This is the reality of LOS warfare, in that, if you can sustain the speed of the round at the muzzle (via rocket propulsion), there is not a tank on the planet which can withstand any of the modern 120-125mm rounds.  And using the concept of a Modern ONTOS (LOSAT has been killed by politics by CKEM can go on systems as small as a robotic MULE) you can guide eight shots before the first enemy round hits you.

And this is the critical reality we are talking about here.

Because it's not the first minute that counts.  It's the first 10-15 seconds which decides tank combat at anything under about 2,500-3,000m these days.  Everyone (including the Russians) have modern fire control and decent rounds. Such that anybody shooting that gets a hit is likely to get at least a mission kill as the turret jams or the vehicle stops moving.

If a missile carrier can fire 8 rounds in 10 seconds it beats 8 tanks with manual loading or 4 tanks with autoloaders and it does so at distances beyond that which their own kinetic energy penetrators can guarantee a hit.

If you cannot beat the rapid fire, cheap, solution at LOS distances.  And you cannot bring enough tanks to beat an enemy equipped with T-90 or Leo-2A6 to a distant theater quickly enough, then you had better go for an alternative 'netcentric' approach which puts the shooter into NLOS and saturates any Automatic Protection Systems with MRSI simulshots.  We could do exactly this, begin killing enemy tanks in maneuver warfare SOONER and FASTER that could be achieved with direct fire systems.  But we would first have to show that these thin skin, easily deployed, easily hidden, bushwackers can also survive 4th generation warfare against whomever we label insurgents, fighting with RPG at <200m distances.

The irony then becomes that in a role for which they are not optimized, tanks remain able to soak a lot of desultory fires with minimal damage gen-after-next 'light' systems are better at open field maneuver warfare.

If we could bring small scale Wiesel type robotic vehicles into MOUT service with light cannon and ATGW atop minimally armored hulls in the 5-10 ton class, we could ditch tanks altogether and save HUGE amounts of money in yearly maintenance and training alone.  But so long as it's high-tech vs. old-iron in street fighting, the tankers will snicker and keep their rides because, nominally, they are 'cheaper' to shoot up.

Offline Avimimus

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Re: Mortars as anti-tank weapons?
« Reply #5 on: March 22, 2010, 09:40:20 pm »
An extremely interesting article.

I was actually thinking about this situation a few months back. Cheaper guided rounds mean that moderately high value targets (such as tanks) will become increasingly vulnerable. Improved battlefield surveillance technology will become extremely important for targeting indirect fire. Of course, even with their high fuel costs and other limitations heavy armour will continue to dominate for a few decades if only due to the higher protection it provides from RPG ambush. Tank guns are also fairly effective weapons and improved targeting equipment and survivability will make the next generation of tanks competitive. However, it would seem that they are on the way out.

There are two obvious problems with such mortar systems as anti-tank weapons: The first is the relatively long flight time for the projectiles which increases the chance of a target moving out of the view of the targeting system. This means that remote targeting capability and communications will be very important (in order to have multiple perspectives on the target or a good free-fire area for an actively guided uncaged round). The second is that such weapons have fairly large minimum ranges. However, this second problem can be solved via the use of a secondary anti-tank missile system which won't suffer from the long flight times that weaken such systems at medium to long ranges.

Another nice feature about a guided mortar is that the launcher can remain hidden or relocate (and with a guided round the initial trajectory doesn't have to be perfect so it can fire without having a perfect orientation).

Offline GLAR

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Re: Mortars as anti-tank weapons?
« Reply #6 on: March 23, 2010, 12:14:10 am »
Avimimus,
The key to defending against guided hi-loft weapons is early intercept in the midcourse or tipover terminal phases with either an accompanying vehicle (Goalkeeper on tracks rather than Gauntlet for a choice...) or onboard systems that can fire-on-move defend.  Lasers would be optimum.  APS close in protection risks saturation while, coverage may not be ideal for steep divers.  Ideally, you want to be able to drive out from under the threat acquisition footprint and keep your formations massed up (i.e. to avoid the SFW saturation option).

Assuming there is a strapdown IMU if not full up GPS system (acquisition window on the signal is going to be short) involved and they either have a sufficiency of squib rockets or switch to paravanes; the ability to duplicate the 'fire over here, turn at midcourse there' option is possible as it is with Excalibur and the other CLGP.  Indeed, if I was going to put a smart round out there with semi-precision capabilities (10m CEP overlap and MRSI will solve most tactical problems, especially at extended ranges outside cities), it would not be one which came with an endemic seeker cost and signature verification/update requirement with the home user.  For the cost, there are simply too many ways to mask or dazzle such a system template so that it doesn't lock up.

That said, for home-nation use, if we can put signature classification on the WASP in the early 1980s, imagine what JASSM/JAGM and LOCAAS could have done.  It's all in the cost and the competition with existing sweetheart (cough, TOW, Hellfire, Maverick, SDB) weapon classes as well as the R&M turf protection agreements.

The big problem with tank guns is that they are in fact NOT all that great.  AFAIK, we are still using 1980s technology not just to load them (like a trapdoor carbine Custer would be familiar with) but we also have no autonomous, onboard, means to scan the volume, sort and assign tracks for multiple, defiladed, decoyed or 'other' (dump truck as technical etc.) targets without a man slewing the turret and holding the aimpoint.

Which is just ridiculous for speed of initial engagement and reduction of threat.  Especially if you are fighting in cities which is the only place Armor isn't crushed by air because the LOS is so short.

Indeed, I see no point in having the turret be manned at all since three guys in the way of 10 ton ram coming back is a recipe for mutilation and despite the blowout panels and the Chobham, the vulnerability to brewup colocation is extreme.  Pull those three guys out and suddenly you have room for an autoloader, an APS with deep magazine and maybe a 25-35mm coax that doesn't require main gun expenditure on cheap targets like APC or Infantry behind a berm.  Which is to say 80-90% of a tank's proper work in most SSC/LIC conditions.

Alternately, you can narrow the target signature of the turret block (like the M1A4 was supposed to) and lighten the overall dead weight by about 30-40%-

http://www.militaryimages.net/photopost/data/501/TTB001.jpg

RPG (and various other, close in) defense only comes at an enormous weight penalty with ERA, engine slats, a boat-hull belly package and various protection for the back-up-top exposed engine and 'gunners'.  Which of course means the TC and Loader are no longer helping to service that big tube and all the money you've wasted on things like CITV and tank-talk was for nothing.  Let us also not forget the Abrams driver that had a pencil sized EFP go through the side the tank on his left, pass through his back cushion and head on out to through the right.-

http://newsmine.org/content.php?ol=war-on-terror/iraq/mystery-weapon-knocks-out-m1a1-abrams-tank.txt

That shocker came from a 'special' RPG head against a fully TUSK'd machine.

IMO, the Abrams that goes out to rescue someone being ambushed is a fast ambulance.  The single Abrams that accompanies a platoon walkabout in badguy country is a fire magnet.  And the masses of armor that can accompany multiple patrols in suppressing a populace that greeted us with open small arms is not going to look like an MBT.

Why should it?  A wiesel with a 40mm glacis and 5-10mm all round plus option extra boltons is going to beat most small arms while Trophy and reactives can do for the LAW problem if not the IED.  It's 20mm cannon, even if necessarily upgraded to 30mm, with the proper active fuzed rounds-



Means you have the ability to suppress defiladed threats rather than obliterate the house or apartment block they are in.  This has been a known feature of high velocity autocannons since the Falkands when Scimitar were shooting up troops in trenchlines 'on the diagonal', through feet of dirt.  A large element of which is inherent to a tall turrent and +45`/-15` elevation capability 'also good for mountains, fences or high rises'.

They are small enough to negotiate most streets without problems-

http://img.photobucket.com/albums/v101/He219/photobucket/new/CAAOXAVD.jpg

Even if there are parked cars on each side.  They are quick as lightning at around 70-80kph (31hp/ton) yet have a good range .  Yet with a ram (little more than a steel tube on a plow type extension) they will go through most garden walls just like an Abrams.

Unlike an Abrams, you can actually walk beside them when they fire their main weapon.  And they are _dirt cheap_ to use.  Outside the COIN mission, they are light enough to be lifted inside a CH-47 or 53 which means that they can be rapidly emplaced or recovered and repaired/regenerated to act as scout/screen forces for heavier units.  And of course if you are doing forced entry 'the old fashioned way' with a C-17 off a highway strip, you can chuck a huge number of these things in the back for every Abrams or Bradley: 2.75 tons versus 68 or 30.5.

IMO, the day of the battlefield infantryman except as local security is also over.  Every unit, including airborne and special ops, should be mounted, fires-heavy, units.  But that doesn't mean they need to roll into combat on a semitruck weight class mobility platform.

And if the infantry isn't there then the last redoubt of the infantry-support role for the tank collapses around tread head ears.

In maneuver warfare, you need to disperse into cellular formations that can cross support without being massed.  Netfires and NLOS can handle the 20km+ mission.  But for the <15km 'urban' mission; you need mortars that can hold the pace and intensity of fires driven ops to support heavily contacted forces without (ideally) direct fire exposure themselves.  And you need a large number of platforms that can charge ahead, to clear the road and (for LIC) hold a position towards which the main van of vehicle mounted or at least supported infantry can flow.

This goes beyond security force, particularly in MOUT, because it pushes the (light) tanks out ahead of any residual infantry unit like a dustpan to a broom.  So that they can kill a displacing enemy as he goes by.  No abrams can do this in small numbers at the slow pace they use.  But it might very well be that 'tanks in our rear!' could have a whole new meaning if they are employed fast enough to avoid becoming associated with infantry rates of advance but once again are seen as breakthru and exploitation elements, even in cities.


GLAR


Offline Berekhat

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Re: Mortars as anti-tank weapons?
« Reply #7 on: March 23, 2010, 12:41:35 am »
@GLAR

"That shocker came from a 'special' RPG head against a fully TUSK'd machine"

Not in 2003, which is the date quoted right up top in your link, it didn't.

Side armour on an Abrams has been penetrated many times, and TUSK, had it been deployed during that incident, likely would have stopped what was clearly not a very powerful warhead.

Offline Just call me Ray

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Re: Mortars as anti-tank weapons?
« Reply #8 on: March 27, 2010, 09:53:19 pm »
or in the more typical-for-mortars high trajectory mode?

I would imagine that if this were not the case, it would be unlikely that they would be calling it a mortar.
It's a crappy self-made pic of a Lockheed Unmanned Combat Armed Rotorcraft (UCAR), BTW
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Offline Firefly 2

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Re: Mortars as anti-tank weapons?
« Reply #9 on: April 11, 2010, 02:53:08 am »
In ARMOR magazine, there was one idea for the use of a lightweight armored vehicle using a heavy 120mm breechloading mortar firing guided rounds as an "Indirect" anti-tank system.  Ideally, you would be able to use it both for anti-tank indirectly and more general support of infantray.

 So my question is this-- could a 120mm guided mortar round be powerful enough to give the kill probability to make such an indirect anti-tank system viable?

The idea is quite similar to Merlin.
http://www.secretprojects.co.uk/forum/index.php/topic,5166.0/highlight,merlin.html