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A little low calibre for this thread, but I don't feel like starting a new one for medium calibre guns.

 

http://www.janes.com/article/75087/orbital-atk-progresses-new-medium-calibre-munition-development

 

Looks kinda neat. Would like to know more about the 'command guided' 30mm type for sure.

 

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1 hour ago, Belesarius said:

A little low calibre for this thread, but I don't feel like starting a new one for medium calibre guns.

 

http://www.janes.com/article/75087/orbital-atk-progresses-new-medium-calibre-munition-development

 

Looks kinda neat. Would like to know more about the 'command guided' 30mm type for sure.

 

 

It sounds like they are scaling down the 50mm EAPS guidance system.

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Does anyone has this publication ?

 

Richard P. Davitt, "Design and Development of the XM578 APFSDS-T Cartridge for the 152mm XM150 Gun/Launcher: XM803 Main Battle Tank Program (U) ," Picatinny Arsenal Technical Report 4778, December 1975.

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On 11/6/2017 at 2:20 PM, Ramlaen said:

Rarefaction Wave Gun, the bastard child of  traditional large caliber guns and recoilless rifles.


I did a thread on these some time ago.

 

On 11/14/2017 at 10:08 PM, Ramlaen said:

Something I came across while looking for something completely different, a patent on kinetic energy projectiles that lengthen after being fired.

 

SluFeaO.png

 

  Reveal hidden contents

 

 

Extended rods are mentioned in this overview of novel penetrator technologies.

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Wanted the opinion of the forum about guided ammunition for MBTs

 

http://preprod.nexter-group.fr/images/stories/filiales/MUN/char/40055_POLYNEGE_VF.pdf

 

In this case it's a French technology demonstrator (early 2000 I don't have an exact date), but IRC the US have a similar round in development (Plus the M982 Excalibur round that is already in service for artillery).

 

The advantage I see:

 

-Perform the same job than a top attack ATGM while being most likely cheaper (The flight control, electronics and warheads are by all mean the same but it doesn't need a booster)

-Added versatility for MBT (Just send the data from the BMS to the FCS, load the round and fire)

-Slightly faster than an ATGM (600-700 m/s vs 150-300 m/s for an ATGM), so maybe some APS might have a harder time intercepting it (not sure about that though)

 

Cons would be:

 

-The diameter or the warhead is limited by the gun (but the same apply for gun launched ATGM)

-Contrary to an ATGM those rounds have to follow a ballistic arc so in some terrain configuration they might not be able to hit the target.

 

Personnaly I think that the added range and versatility for MBTs is worth it (8km ; fire and forget ; NLOS capability could be a big deal if you have no artillery support available), but perhaps others will see it as a gadget.

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If we are talking active guidance and not INS/GPS my opinion is that

 

-I am really disappointed the XM1111 MRM got cancelled in a rash of short sighted cost cutting.

-Guided rounds fall into the special purpose niche that gun launched ATGMs do.

-Programmable airburst rounds (both the HE and KE variety) seem to have superseded guided rounds due to cost effectiveness.

-NLOS is an attractive potential.

 

 

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On 11/28/2017 at 2:59 AM, Alzoc said:

Wanted the opinion of the forum about guided ammunition for MBTs

 

http://preprod.nexter-group.fr/images/stories/filiales/MUN/char/40055_POLYNEGE_VF.pdf

 

In this case it's a French technology demonstrator (early 2000 I don't have an exact date), but IRC the US have a similar round in development (Plus the M982 Excalibur round that is already in service for artillery).

 

The advantage I see:

 

-Perform the same job than a top attack ATGM while being most likely cheaper (The flight control, electronics and warheads are by all mean the same but it doesn't need a booster)

-Added versatility for MBT (Just send the data from the BMS to the FCS, load the round and fire)

-Slightly faster than an ATGM (600-700 m/s vs 150-300 m/s for an ATGM), so maybe some APS might have a harder time intercepting it (not sure about that though)

 

Cons would be:

 

-The diameter or the warhead is limited by the gun (but the same apply for gun launched ATGM)

-Contrary to an ATGM those rounds have to follow a ballistic arc so in some terrain configuration they might not be able to hit the target.

 

Personnaly I think that the added range and versatility for MBTs is worth it (8km ; fire and forget ; NLOS capability could be a big deal if you have no artillery support available), but perhaps others will see it as a gadget.

 

 

I have been thinking about this a bit.  Here are my thoughts:

For the NATO 120mm, GLATGMs of any sort don't seem to make much sense if they use pure rocket propulsion.  They are very space inefficient because the 120mm cartridge case is strongly bottlenecked:

3uY75QW.png

 

All of the volume inside the ammunition rack occupying the difference between the case diameter and the gun caliber is wasted when using GLATGMs.  This isn't so bad with the 125mm and 105mm guns, because they are not as strongly bottlenecked as the 120mm.  Really, the 120mm NATO smoothbore was designed to do one thing and do it really well, and that is fire the meanest APFSDS rounds on the battlefield so it can kill Soviet frying pan tanks dead.  It's a bit less efficient at everything else, but killing Ivan's endless sea of tanks was understandably prioritized.

 

Wasting volume is an important consideration because volume costs mass.  Every cubic centimeter inside a tank has to be protected by some amount of armor, and armor costs weight.  So wasting any of that space is an inefficiency that adds up surprisingly quickly.

So this gun-launched guided projectile is an improvement over GLATGMs, efficiency-wise because none of the volume of the projectile is wasted by being a rocket motor.  The projectile can, in principle, extend from the maximum overall length of the projectile to nearly the rear inside wall of the case head like M829A3 with all the necessary propellant packed around it.  The only problem is that all the electronics and fin actuators and whatnot in the guided projectile need to be hardened to withstand acceleration inside the gun tube, which is quite a bit higher than the gentler acceleration of a rocket motor.

 

But that still leaves the question of why you would want this in the ammo rack instead of another round of HEAT-MP or APFSDS.  In my opinion, indirect fires are best left to dedicated artillery.  And if the MBTs are out on the prowl without artillery or air support, someone has some explaining to do.

 

The place where I see this sort of round being very useful is on one of those light-medium "expeditionary tanks" that are periodically popular, or even on something like a Centauro.  Those sorts of vehicles are supposed to be light enough that they can be easily deployed internationally to sudden crises in lighter transport aircraft than proper MBTs require.  In that sort of situation, it seems a lot more likely that the expeditionary force won't have proper artillery support, since SPGs have become just as big and almost as heavy as MBTs and will likely be left at home.

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55 minutes ago, Collimatrix said:

snip

 So if I rephrase it:

 

-Better volume efficiency than GLATGM

-Not really useful for an MBT if the combined arms doctrine is carried out properly, plus it decrease the amount of general purpose rounds carried

-Could be useful for AFV acting as a rapid response force or long range recon

 

That raise the question of what will the future expeditionary vehicle look like.

 

Personally I don't think that MBT caliber guns are the way to go (105 - 120 mm) and think that a tandem of 40-30 mm AC plus ATGM is more flexible.

And in the later configuration, ATGM are often strapped externally so you can have a bigger warhead. Granted the volume efficiency problem remain, but it is less prominent since AC round takes less space.

Still it could be a useful concept for existing gun fire support vehicles (MGS, Centauro and all the others)

 

Also truck based SPG can be quite easily used for expeditionary purpose and they pack just as much firepower as tracked SPG.

The French deployment in Mali (Operation Serval) is a testament to that since we were able to quickly airlift 4 Caesar which then chased the enemy in a battlefield roughly the size of metropolitan France.

For more details there is a report from RAND:

 

https://www.rand.org/content/dam/rand/pubs/research_reports/RR700/RR770/RAND_RR770.pdf

 

In my eyes the added bonus having those rounds in MBT is that they are generally closer to the lines which mean a shorter reaction time, if a friendly need support:

 

Direct fire support > Mortar > Artillery > Air support (reaction time wise)

 

So with a multi-purpose warhead those rounds could allow MBT to take the same role than self-propelled mortars with the added bonus of being more resilient to enemy fire (since SPM are often APC based) which would free the later for another front or simply increase the volume of fire.

However saturation and area attack cannot be used with those kind of round (since an MBT can only embark a limited number of said rounds), so they are limited to punctual and high value targets.

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13 minutes ago, Alzoc said:

 So if I rephrase it:

 

-Better volume efficiency than GLATGM

-Not really useful for an MBT if the combined arms doctrine is carried out properly, plus it decrease the amount of general purpose rounds carried

-Could be useful for AFV acting as a rapid response force or long range recon

 

That raise the question of what will the future expeditionary vehicle will look like.

 

Personally I don't think that MBT caliber guns are the way to go (105 - 120 mm) and think that a tandem 40-30 mm AC plus ATGM is more flexible.

And in the later configuration, ATGM are often strapped externally so you can have a bigger warhead. Granted the volume efficiency problem remain, but it is less prominent since AC round takes less space.

So it could be a useful concept for existing gun fire support vehicles (MGS, Centauro and all the others)

 

In my eyes the added bonus having those rounds in MBT is that they are generally closer to the lines which mean a shorter reaction time, if a friendly need support:

 

Direct fire support > Mortar > Artillery > Air support (reaction time wise)

 

So with a multi-purpose warhead those rounds could allow MBT to take the same role than self-propelled mortars with the added bonus of being more resilient to enemy fire (since SPM are often APC based) which would free the later for another front or simply increase the volume of fire.

However saturation and area attack cannot be used with those kind of round (since an MBT can only embark a limited number of said rounds), so they are limited to punctual and high value targets.

 

 

That is an accurate paraphrase, yes.

There is some merit to the AC+ATGM configuration for a light tank.  I am not quite sure what you mean by a "tandem AC," though.  AC+ATGM certainly allows a lot more flexibility in vehicle design, and in particular it allows the turret to be a lot smaller since it doesn't need to handle the enormous gun breech.  IMO, ATGMs from such a vehicle should be fired vertically and then thrust vector towards the target.  Swingfire ATGM had this capability (or close to it) decades ago, and electronics have only gotten better and cheaper since then.  Also, I think there's a case to be made for having this sort of vertically-launched ATGM be a general-issue weapon, not just a specialized item for light tanks.  That would mean that an ATGM crew could get away with exposing only the spotter and guidance module (if SACLOS or beam-riding) while the ATGM tube is hidden behind cover.

 

MBT caliber guns are attractive for anything that's expected to fight MBTs.  It's a lot harder to counter APFSDS than it is to counter ATGMs.  Also, gun ammunition is usually smaller for the same ballistic capability than missiles until very extreme velocities.  Using a gun barrel simply as a tube to fling a rocket out of seems silly, however, unless it's a rocket-assisted, gun-fired projectile, which has some interesting potential efficiency advantages for kinetic energy penetrators.  Gun ammunition will tend to be lighter or smaller for a given number of shots than rockets as a general rule though, and I think that can't be overlooked for expeditionary units, which may be in a precarious logistical situation.  Gun ammunition will tend to be cheaper as well, but I don't think that's an enormous consideration for many expeditionary force scenarios.  Presumably expeditionary forces are being rushed to the scene of an international political disaster in small numbers because getting a force to the scene quickly is the overriding consideration.  If their ammo is expensive, it's not a big deal.

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2 hours ago, Collimatrix said:

I am not quite sure what you mean by a "tandem AC," though.

I just meant a tandem of an AC in combination with an ATGM, not a twin AC or something like that.

May have phrased that one poorly.

2 hours ago, Collimatrix said:

MBT caliber guns are attractive for anything that's expected to fight MBTs.  It's a lot harder to counter APFSDS than it is to counter ATGMs.  Also, gun ammunition is usually smaller for the same ballistic capability than missiles until very extreme velocities.  Using a gun barrel simply as a tube to fling a rocket out of seems silly, however, unless it's a rocket-assisted, gun-fired projectile, which has some interesting potential efficiency advantages for kinetic energy penetrators.  Gun ammunition will tend to be lighter or smaller for a given number of shots than rockets as a general rule though, and I think that can't be overlooked for expeditionary units, which may be in a precarious logistical situation.  Gun ammunition will tend to be cheaper as well, but I don't think that's an enormous consideration for many expeditionary force scenarios.  Presumably expeditionary forces are being rushed to the scene of an international political disaster in small numbers because getting a force to the scene quickly is the overriding consideration.  If their ammo is expensive, it's not a big deal.

In general if you want to use a full pressure gun, you better use a tracked vehicle since it will save weight on the suspension, and the vehicle will also be smaller.

But at the same time a tracked vehicle will often exceed 20 metric ton anyway.

Tracks are more efficient weight-wise but they  automatically put the vehicle above a  minimal weight.

 

The M8 is an exception since it was designed to be just light enough to be squeezed inside a C-130, and I guess that some serious compromises were made for that.

 

Light tanks can potentially be airlifted by tactical aircrafts but have, generally, a greater logistical trail than wheeled vehicles (higher fuel consumption and no parts commonality with APC and IFVs deployed alongside them) which is also a problem for an expeditionary force. Also their effective range will be smaller.

 

A Centauro II will barely fit in an A400M and for the US army to airlift such a vehicle would require the use of a C-17 (which is not as flexible as a C-130 in term of possible landing zone).

The MGS will fit in a C-130 thanks to it's unmanned turret but it's nowhere near the capability of a Centauro II (and most likely of a B1 Centauro as well, especially in the AT department) but it's quite an old design anyway.

If it were to be remade nowadays, I think it would end up heavier and larger.


In the end I think that there is two school:

 

-The European one which use heavy (25-30 metric ton) IFV-based vehicles in combination with the A400M (which is a sort of heavy tactical aircraft). The vehicles may use either a gun (which is not the best idea for wheeled vehicles) or an AC+ATGM combo

-The US that use lighter and less protected wheeled vehicles (Stryker family) and if a bigger vehicle is needed will just use a C-17 and land it on a better airstrip.

 

In the end it mostly comes down to the US having access to a heavy lift strategical aircraft and having vastly superior logistics than European country, while the European will have access to a better tactical aircraft.

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5 hours ago, Alzoc said:

I just meant a tandem of an AC in combination with an ATGM, not a twin AC or something like that.

May have phrased that one poorly.

In general if you want to use a full pressure gun, you better use a tracked vehicle since it will save weight on the suspension, and the vehicle will also be smaller.

But at the same time a tracked vehicle will often exceed 20 metric ton anyway.

Tracks are more efficient weight-wise but they  automatically put the vehicle above a  minimal weight.

 

The M8 is an exception since it was designed to be just light enough to be squeezed inside a C-130, and I guess that some serious compromises were made for that.

 

Light tanks can potentially be airlifted by tactical aircrafts but have, generally, a greater logistical trail than wheeled vehicles (higher fuel consumption and no parts commonality with APC and IFVs deployed alongside them) which is also a problem for an expeditionary force. Also their effective range will be smaller.

 

A Centauro II will barely fit in an A400M and for the US army to airlift such a vehicle would require the use of a C-17 (which is not as flexible as a C-130 in term of possible landing zone).

The MGS will fit in a C-130 thanks to it's unmanned turret but it's nowhere near the capability of a Centauro II (and most likely of a B1 Centauro as well, especially in the AT department) but it's quite an old design anyway.

If it were to be remade nowadays, I think it would end up heavier and larger.


In the end I think that there is two school:

 

-The European one which use heavy (25-30 metric ton) IFV-based vehicles in combination with the A400M (which is a sort of heavy tactical aircraft). The vehicles may use either a gun (which is not the best idea for wheeled vehicles) or an AC+ATGM combo

-The US that use lighter and less protected wheeled vehicles (Stryker family) and if a bigger vehicle is needed will just use a C-17 and land it on a better airstrip.

 

In the end it mostly comes down to the US having access to a heavy lift strategical aircraft and having vastly superior logistics than European country, while the European will have access to a better tactical aircraft.

This is what Colli means by "rocket-assisted, gun fired projectile" by the way: 

:P 

 

 

 

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