Secondary Armament on MBTs

[sgtgunn]

Hi,

Just curious on people's thoughts regarding secondary armament on MBTs.

As a former US Army tank crewman (and gunner) I would have loved to have a heavier caliber coaxial MG than the 7.62mm M240. Something that would have allowed me to make better use of the tank's sights and FCS for long range shooting, and would have had the ability to defeat light armor and soft skin vehicles as well.

IMHO a co-axial .50cal would be ideal - either a Browning M3 (M2 with higher ROF) or a GAU-19/A GECAL 50. The .50cal SLAP-T round can defeat 34mm of armor at 500m which would make the weapon useful against light armored vehicles - no need to waste a 120mm main gun round. A .50cal coax with a high rate of fire would also be very useful in dealing with built up terrain - a GAU-19/A spitting out 2000 rpm could demolish most hard cover in short order. Plus the psychological effects of such a weapon would be substantial. As I understand it when the XM1 was being developed, one of the proposals for secondary armament (advanced by US Army tank crewman with combat experience in Vietnam) was TWO M2 .50 cal machineguns - one on either side of the main gun, which would fire simultaneously. Later it was changed to mounting a the Bushmaster M242 25mm chaingun on one side of the maingun, and the M240C 7.62mm MG on the other. This was deleted becuase of cost.

I'd also like to see the commanders M2 .50cal replaced by a remote (like on the M1A2 TUSK) weapon station with either a 40mm AGL with airburst capability or the new 25mm OICWS. Having MGs for air defense on MBTs these days seems a bit anachronistic - I think having an AGL to be able to rapidly supress ATGM or RPG teams would be better.

Any thoughts?

Adrian

 

[Gremlin29]

Since you have professional experience I will defer to your expert opinion. By the thread title the first thought I had was that the 7.62 seemed oddly inadequate for a modern MBT for the very reasons you pointed out. In fact, I never could understand why they didn't put Ma in their to begin with. As for the TC, I'd be shocked if they even considered anything that wasn't standard conventional ala the 50 cal. I always thought the TC was unbuttoned most of the time for better situational awarness, in which case the existing weapon seems to be appropriate however, this may be passe for many years, I honestly don't know. If that's not the case, a remote weapon makes sense but wouldn't it be more practical to stick with a 50 cal?

Also and again, I'm not a tread head but.... I wonder in relation to our experiences in Iraq and Afghanistan if we aren't trying to taylor our forces a little too much for LIC which would be a huge mistake, in my opinion. We should be able to switch between LIC and HIC but we never seem to get the funds for both, it's always an either - or proposition.

 

[sgtgunn]

US tank commanders are (or were) trained to fight unbuttoned (or at least semi-unbuttoned with the TC hatch in the "open protected" position) but two things seem to be changing that. First is the FBCB2 & Blue Force Tracker battlefield information systems and the commander's independent thermal viewer which now potentially monopolize the TC's attention inside the turret. Secondly were the large numbers of TC's killed or wounded by snipers/small arms fire in Iraq. The older M1 & M1A1 Abrams had provisions for firing the .50 cal while buttoned up. The M1A2 eliminated that capability (to make room for the CITV I believe) and went back to the old school pintle mounted .50 cal that the TC had to be fully exposed to fire. The TUSK upgrade restored the ability to fire the .50 cal buttoned up by adding a remote weapons station similar to the one mounted on HMMWV and Strykers. The RSW can mount a M240, M2 .50 or MK19 AGL - but as far as I can tell, the .50 cal is what is typically mounted on the M1A2 TUSK (MK19 have fallen out of favor in Iraq due to close engagement ranges and collateral damage issues). Apparently TUSK can also include a 2nd .50 call mounted externally on top of the main gun barrel near the mantlet, electrically fired and bore sighted to gunner's primary sight - similar to what the Israelis have done in the past.

I like the idea of a MK19 or similar weapon for the TC as it gives the tank additional capabilities beyond what the other weapon systems provide. An AGL can cover dead space, reach out to 2200 meters, and would be highly effective in suppressing ATGM or RPG teams. Using a newer AGL, like the MK47 Mod 0 allows the firing of programmable air burst grenades with increased lethality. The M430A1 40x53mm HEDP grenade can penetrate 76mm of armor plate, giving the TC a good secondary light anti-armor capability. GD has developed the M1001 40x53mm Canister grenade which fires 115 17gr. flechettes out to 100m giving the TC excellent close in defense capability. There is potential for less-than lethal rounds as well, which could be useful in LIC. Ideally a 40mm AGL with dual feed capability could be developed, allowing the TC to select between 2 types of ammo. In cases where the AGL is inappropriate a .50cal or M240 could be substituted.

I share your concern about excessively tailoring our forces for LIC (or even for a specific theater). The MRAP program is a good example - hundreds of million dollars to purchase these vehicles, which were great for Iraq, but are proving to be too big and heavy for Afghanistan, and wouldn't last 30 seconds in a HIC environment. Politics has forced the US into an obsession with force protection, even to the detriment of combat capability and of cost.

The idea that no casualties are considered acceptable is patently ridiculous, and such a cautious attitude is bound to get us in trouble down the line.

Can you imagine, in this day and age with modern 24 hour media and political attitudes trying to carry out an operation like Overlord in WW2? From June 6th to the end of August the allies sustained 36,976 killed, 153,475 wounded and 19,221 missing. Can you even fathom any western government today surviving after losses like that? People would be rioting in the streets.

Adrian

Since you have professional experience I will defer to your expert opinion. By the thread title the first thought I had was that the 7.62 seemed oddly inadequate for a modern MBT for the very reasons you pointed out. In fact, I never could understand why they didn't put Ma in their to begin with. As for the TC, I'd be shocked if they even considered anything that wasn't standard conventional ala the 50 cal. I always thought the TC was unbuttoned most of the time for better situational awarness, in which case the existing weapon seems to be appropriate however, this may be passe for many years, I honestly don't know. If that's not the case, a remote weapon makes sense but wouldn't it be more practical to stick with a 50 cal?

Also and again, I'm not a tread head but.... I wonder in relation to our experiences in Iraq and Afghanistan if we aren't trying to taylor our forces a little too much for LIC which would be a huge mistake, in my opinion. We should be able to switch between LIC and HIC but we never seem to get the funds for both, it's always an either - or proposition.

 

[Waylander]

I have to say that I like a 7.62mm as a coax.

You can just carry alot more 7.62mm ammo. Carrying 12.7mm or even something like a 20mm (The french tried that with their AMX-30 but got rid of it fairly early) would reduce your ammo under what I would consider necessary for a MBT.
In the end often enough one wants to put as meany metal into the air as possible and thus a GPMG is the better choice.
If one really wants to be able to touch a group of soldiers at a longer distance new ammunition is the way to go.
The US is awfully slow in adopting new 120mm ammunition especially when one thinks about how they are engaged in Iraq.
What do they have? For most of the time they just had a glorified HEAT (MPAT) and than the canister was added.
Not what I would call a well rounded ammo combination.
There are many many more 120mm smoothbore solutions out there which would enhance the ability of the Abrams to engage enemy crunchies.
We have a simple but working HE from Sweden.
France has their HE-T Mk.II with a more sophisticated fuse.
The Israeli APAM and the German DM-11 are the most sophisticated 120mm HEs out there with aeverything one wants from a HE (quick fuse, delay fuse, airburst).
Also PELE is available. A KE which generates alot of shrapnell after penetration and is ideal for attacking men in rooms without to much danger for civilians nearby.

IMO one should go on using a GPMG as the coax but as you said one should also add an independent weapons station which can be used by both loader and tc.
Most weapons sations these days are able to take either a GPMG, .50cal or a AGL so what one puts onto it is what one prefers.

And compared to many other weapons (LGBs, JDAMs, ATGMs,...) which are used to blow away mud compounds and houses these days a 120mm is still very cheap.

 

[Firn]

First of all I want to state that the ex-tankers here certainly know better than me in this area.

Nevertheless I collected a wealth of information in the thread about the 120mm mortar as indirect and direct firesupport on armored AFV. In one of those papers it was interesting that during the initial fights in urban areas of Iraq in the third Gulf war the .50 was reported to be potentially more prone to cause collateral damage than the 120mm HEAT because it was overpenetrating so much. The Heat annihilated pretty much everything in the targeted room but was more localized.

Said that I believe that a GPMG should probably be the standard companion of the 120mm, perhaps with the option to externally mount an coaxial .50 like sgtgunn mentioned. However first of all a wide array of ammunition should be available for the main gun. Waylander already gave a good insight into possible choices. Perhaps a HESH round could be another interesting option.

I like the idea of a MK19 or similar weapon for the TC as it gives the tank additional capabilities beyond what the other weapon systems provide. An AGL can cover dead space, reach out to 2200 meters, and would be highly effective in suppressing ATGM or RPG teams. Using a newer AGL, like the MK47 Mod 0 allows the firing of programmable air burst grenades with increased lethality. The M430A1 40x53mm HEDP grenade can penetrate 76mm of armor plate, giving the TC a good secondary light anti-armor capability. GD has developed the M1001 40x53mm Canister grenade which fires 115 17gr. flechettes out to 100m giving the TC excellent close in defense capability. There is potential for less-than lethal rounds as well, which could be useful in LIC. Ideally a 40mm AGL with dual feed capability could be developed, allowing the TC to select between 2 types of ammo. In cases where the AGL is inappropriate a .50cal or M240 could be substituted.

I fully agree. An dual feed AGL fitted on an RWS with high elevation and depression would be an amazing capability. Ideally the RWS should have beside the a heavy weapon station (HMG, AGL) alway an coaxial GMPG with a lot of ammunition. This should only be slightly more expansive than a single heavy WS on the RWS but allow the crew (TC, loader) to tailor the response to the thread and retain the ability to suppress the enemy far longer.

 

[Waylander]

I don't see huge benefits a HESH gives compared to a modern HE-FRAG with several different modes.
It's more the other way around.
A HESH is usefull if you want to have something that gives a good bang on impact but a modern HE is much more versatile.
The capability of getting an airburst or delay fuse is IMHO much better than a simple HESH.

 

[Chino]

double

 

[Chino]

I was a former rifleman conscript/reservist. Here's my 2 cents...

MBT should never be unsupported by other AFVs as well as mounted or dismounted infantry.

The other AFVs could be wheeled or tracked IFV etc and these would have the 20 - 30mm armament. Therefore it is unnecessary for the MBT, with such limited space for the weapon and its ammo, to mount such a weapon.

Regarding the 40mm AGL as TC/cupola mount: I again prefer the commonly found .5. Using SLAP, incendiary or ball, they can cover a great deal of roles they don't need the main gun for. The CIS50 is the best choice vs the obsolete M2HB as it can load two kinds of ammo at once, and switch between the 2 different types with a flick of the switch.

Also, for close in defence, an MG for the TC is still best. If there are enemy infantry within meters of the tank, the TC can spray them with his MG whether 7.62 or .5.

A 40mm round has a minimum arming distance of at least 20m, which means in the situation mentioned above, the TC cannot use the mounted 40mm and will have to fight them off with his personal weapon.

If you really need the tank to have arc-trajectory explosive weapon, you can simply give the TC a handheld GL, either a single shot or a revolver multi-shot. There's no rule to say that every weapon on a tank has to be mounted. And even a revolver GL is very compact. And handheld GLs are etremely easy to use and almost maintenance free.

The IDF, for example, has 60mm mortars mounted for the TC though I am not extremely certain what ammo they carry. (Could be just illum?)

In SAF several types of supporting IFV (including soft-skinned) already mount the 40mm, so again, no real need for the MBT to.

 

[Waylander]

Giving the TC a mounted weapon at all is kind of a question of philosophy.
In germany for example the TC has not mounted MG at all, only the loader has his GPMG.
The TC should concentrate on commanding the tank.
And the loader is also the one who is going to get a weapons station.
One has to remember that every additional weapon and system on the roof of a tank restricts the TC's ability to use his independent TI and also restricts the viewfield when buttoned up.

In the end I would propose the following.
For many tanks there are special urban ops kits available these days. Secondary armament can be just as modular.

If a tank is requested to go into an urban area to support the infantry there or to perform some kind of thunder run against low skill/tech opponents one can mount additional weaponry.
The modern weapons stations are already modular so if one puts a .50cal, a AGL or a GPMG onto them is up to what I think is usefull and what is available.
Give the TC the ability to mount a GPMG with a modern gunshield and put an additional .50cal onto the main gun like on the TUSK or some Israeli tanks.
Add to that the additional protection kit and one has a fine urban support tanks without much additional burden to your armed forces.

Such a vehicle would have something like 2x GPMGs, 2x .50cal, 1x 120mm and the personal weaponry of the crew.
A reasonable all around protection againest handheld AT weapons and 3-4x TIs for the crew add alot combat capabilities, too.

If you are doing traditional field work one just strips the tank of some or all of the modular stuff.
I for one wouldn't want to replace the 7.62mm coax wit something else.
I don't know about the M240 of the Abrams but the MG3 coupled to the FCS of the Leo II is reasonably accurate at upt to 1 klick and with it's high rate of fire is also abe to surpress enemy dismounts at even longer range.
And I wouldn't call sending a 120mm airburst to an enemy squad some 3 klicks away a waste.
And I doubt that one can supress enemy ATGM teams very good at longer distances with a 40mm AGL. 120mm HE is the way to go then. And at closer range a 1200rpm GPMG brings alot of lead into the air to surpress enemy teams.

 

[Firn]

To come back to the AGL

I like the idea of a MK19 or similar weapon for the TC as it gives the tank additional capabilities beyond what the other weapon systems provide. An AGL can cover dead space, reach out to 2200 meters, and would be highly effective in suppressing ATGM or RPG teams. Using a newer AGL, like the MK47 Mod 0 allows the firing of programmable air burst grenades with increased lethality. The M430A1 40x53mm HEDP grenade can penetrate 76mm of armor plate, giving the TC a good secondary light anti-armor capability. GD has developed the M1001 40x53mm Canister grenade which fires 115 17gr. flechettes out to 100m giving the TC excellent close in defense capability. There is potential for less-than lethal rounds as well, which could be useful in LIC. Ideally a 40mm AGL with dual feed capability could be developed, allowing the TC to select between 2 types of ammo. In cases where the AGL is inappropriate a .50cal or M240 could be substituted.

With a high elevation and the relative low charge of the 40x53 grenades the AGL can function as a kind of small mortar. With a simple integrated FCS coupled with a laser range finder and good sights it should be easily able to fullfill a similar function with great speed and good accuracy. So it offers a unique set of capabilities. Once again a light coaxial should round the package off.

Giving the TC a mounted weapon at all is kind of a question of philosophy. In germany for example the TC has not mounted MG at all, only the loader has his GPMG. The TC should concentrate on commanding the tank.

And the loader is also the one who is going to get a weapons station.
One has to remember that every additional weapon and system on the roof of a tank restricts the TC's ability to use his independent TI and also restricts the viewfield when buttoned up.

Given that at least one RWS is now pretty much the standard on almost all new AFV I fancy that the "loader" remains a very important part of the team. The TC, the gunner and the driver are able to focus on his core competences with the loader given helping help not only during combat.

I don't see huge benefits a HESH gives compared to a modern HE-FRAG with several different modes.
It's more the other way around.

A HESH is usefull if you want to have something that gives a good bang on impact but a modern HE is much more versatile.
The capability of getting an airburst or delay fuse is IMHO much better than a simple HESH.

There is no doubt that overall a modern HE-FRAG has greater versatility. The HESH does some things best, but the amount of ammunition is of course limited.

 

[Vajt]

How about redesigning the smoke launchers a bit so that they can have limited movement (like a mini turret) to be able to also launch HE grenades and not just smoke. If you combine that with the Metalstorm concept (specially for the capability to line a row of rounds per tube) you could have a few tubes with smoke rounds and some with HE rounds.

-----JT-----

 

[kato]

It's cheaper to just mount something like SKWA for that purpose. Either a movable version like this one on the Puma, or a simple "turret ring" Rheinmetall also offers. In addition to the smoke grenade launchers that is.

 

[eckherl]

Geez,

Do we not have enough crew served weapons bristling on current U.S tanks. I have never been a big fan on going to a larger gunners coax mg, the M2 for a TC provides sufficient protection against a wide variety of secondary targets. A gunners coax mg`s primary duty is to not kill with pin point accuracy but to suppress the threat area, with this in mind it needs lots of ammo to perform that mission, more than what a 50 cal or larger weapons system could provide.

With all this said I would like the U.S to go back to the M85 due to a higher rate of fire over the M2, you can use the same TC`s mounting systems that are currently on all M1 series tanks, you can also use the M249 coax mg in the event of a emergency for those out there that was not aware of this fact.

TC 50 cal - secondary targets, area suppression be it air or ground.
Gun mount Tusk upgrade 50 cal - Sniping or suppression.
Gunners coax - area suppression, light skinned vehicles.
Loaders mg - area suppression, light skinned vehicles.
Big boom stick - cannister round and a variety of new Heat projectiles.

I think that the U.S has the secondary armament factor covered on their tanks.

 

[Vajt]

It's cheaper to just mount something like SKWA for that purpose. Either a movable version like this one on the Puma, or a simple "turret ring" Rheinmetall also offers. In addition to the smoke grenade launchers that is.

That also works!

-----JT-----

 

[kato]

I think that the U.S has the secondary armament factor covered on their tanks.

True, it's more like one could consider starting to reduce secondary armament.
For example, one could replace all those secondary guns on the top of the turret with a single cupola - say a .50cal/7.62mm coax mount, stabilized, aiming software tied into tank FCS, perhaps a linkless feed system going to below armour.

 

[Firn]

True, it's more like one could consider starting to reduce secondary armament.
For example, one could replace all those secondary guns on the top of the turret with a single cupola - say a .50cal/7.62mm coax mount, stabilized, aiming software tied into tank FCS, perhaps a linkless feed system going to below armour.

That is what I wrote or wanted to say in the posts above, with an AGL instead of the .50. But they are of course interchangable.

With good optics the loader and the gunner can thus focus on the observation of the environment, the TC on commanding and whatever he needs to do and the driver on driving.

 

[Lopex]

That is what I wrote or wanted to say in the posts above, with an AGL instead of the .50. But they are of course interchangable.

With good optics the loader and the gunner can thus focus on the observation of the environment, the TC on commanding and whatever he needs to do and the driver on driving.

The AGL would not be interchangeable as a coax to the main armament with any MG because of the often low elevation limits. As mentioned in an earlier post the coax MG is for suppression and has a high rate of fire to compensate for the often poor accuracy, The FCC is only ever programmed for the various armament rounds. The coax is a spray pray and adjust affair. Major adjustments and calculations on the FCC would be needed and the wind information would go out of the window when firing a AGL round up in the air.

 

[Firn]

The AGL would not be interchangeable as a coax to the main armament with any MG because of the often low elevation limits. As mentioned in an earlier post the coax MG is for suppression and has a high rate of fire to compensate for the often poor accuracy, The FCC is only ever programmed for the various armament rounds. The coax is a spray pray and adjust affair. Major adjustments and calculations on the FCC would be needed and the wind information would go out of the window when firing a AGL round up in the air.

I think you followed the discussion not too carefully. Kato talked about the secundary armament in top of the turret, in short of an RWS with two coaxial weapons, one heavy, one medium.

Other than I mostly agree.

 

[Waylander]

The coax is a spray and pray affair?
A GPMG coupled to the FCS of a modern MBT is much more accurate than any other GPMG out there be it employed on bi- or tripod.
A good gunner brings at least the second burst right onto the target at up to 1 klick and more and that within no time after lasing the target.

The rebells in A-stan had to find this out the hard way when they encountered Canadian and Danish Leos in the field.

Firn already mentioned the other thing.

 

[Lopex]

The coax is a spray and pray affair?
A GPMG coupled to the FCS of a modern MBT is much more accurate than any other GPMG out there be it employed on bi- or tripod.
A good gunner brings at least the second burst right onto the target at up to 1 klick and more and that within no time after lasing the target.

The rebells in A-stan had to find this out the hard way when they encountered Canadian and Danish Leos in the field.

Firn already mentioned the other thing.

I can only call it as I have seen it on the CR2. The coax was never even bore sighted. This was the reason a tank commander was killed by friendly in Iraq. The first shot can be so far off with the cross hair on the target its scary. Like you say a good gunner will correct but its its never bore sighted what chance do you have?