2S38 Derivatsiya-PVO 57-mm SPAAG

What kind of giudance system will the 57 mm shell use? Laser? If so it seems difficult to mantain a laser beam focus on a fast moving target like cruise missile or aircraft.

Depends... the current models seem to be semi active laser homing... ie the target is tracked and painted with a laser beam.

Kornet-EM already uses an auto tracker to follow the target automatically and guide the outgoing missile with a stabilised laser... Tunguska and Pantsir and TOR also use similar video based auto tracking systems, as does the Hokum and Havoc.

Considering the size of the ammo an IR sensor or MMW radar sensor should also be options too some time down the track.

With an explosively ejected rear cap a laser beam riding design is also likely possible.

Garry B, there are guided shells for every caliber (bigger calibers included), and there are guns that can fire them at low rates of fire. If fact this caliber has been surpassed for low rate of fire configurations, and would not be need of it. You know it. This is not the key point in the development of this new gun of 57mm.

Also the range if 12000m is not the key point of this new gun. The Russian engineers reached this range for a gun of 57mm in the 1960s with the AK-725 of the naval artillery, which maximum range is 12700m. I have not doubt that a gun of today can surpass it, but again we have higher caliber guns doing it for low rate of fire, without a need of new low rate of fire guns of 57mm.

So what you are asking is why don't they go with a 125mm gun... much better range, bigger payload, much easier to make guided, already in service.

This weapon is supposed to take over from the 30mm cannon in the air defence and IFV role. That means it needs to be able to hit small manovering aerial targets but also penetrate armour at battlefield ranges... ie 2-3km.

In other words it needs to be able to defeat enemy IFVs at 2-3km and so the 125mm round might be able to do that but an armoured vehicle with a 125mm gun is a tank, so rather than using a 125mm gun on your IFVs and SPAAGs, you could give that role to your tanks and SPAAGs.

For use against enemy IFVs the 125mm is over kill and too heavy. 57mm rounds are much better suited and have been developed together with the Navy so both branches can use the guns and the ammo.

The key question to improve in this gun is the rate of fire. Here is where your comment about successive steps makes sense, because high rates of fire have been reached for 30mm guns, and the 57mm guns are the next step.

How high a rate of fire does a PKM fire?

The MG-42 from WWII fires at 1,800rpm, so why does the newer PKM fire at 600rpm?

They had the ShKAS and the Ultra ShKAS firing at enormous rates of fire in WWII mounted on aircraft so it is not a problem to get the high rates of fire, but a very high rate of fire for MGs has been found to be wasteful in most applications.

The exception is where time is short or the targets are moving very fast like firing from fast moving aircraft at ground targets or aerial targets...

It is the same for the 57mm gun... a Warrior IFV wont be moving super fast so firing a few rounds of APFSDS rounds is all that is needed... you don't need to fire a rapid 20 round burst. Against fast moving small aerial targets it makes sense to use guided rounds not a high rate of fire of dumb rounds to get a kill.

I commented that your prediction of 120-200 rounds per minute for the new 57mm falls clearly short, and that it was starting from the floor stablished by the ZSU-57-2, like if it would be the state of the art. Finding a little about 57mm guns we can see how the Russian engineers surpassed long time ago this rate of fire. The A-220 gun of 57mm designed as naval artillery piece is able to reach 300 rounds per minute, and technologically this is a gun of the 1970s.

I rather doubt the new gun will fire faster than 300rpm because as I said... there is no need for a very high rate of fire... most targets will be engaged with single shots or a burst of 2-3 rounds at most.

I would expect for the new gun of 57mm to reach a rate of fire of 500-1000 rounds per minute. I open the range because I have not enough data to close it more. With a 57-1 configuration, this gun would not be able to work as machine gun for air defense purposes, creating areas of high density of fire, but it would be enough in multiple barrel configurations. It would make this gun able to replace the 30mm gun used in the SA-22 Pantsir (thinking about its successor), and would be also enough to replace the ZSU-23-4 as air defense weapon. And these are likely the two biggest roles that can reach the new gun.

It will not use its rate of fire to kill aerial targets... it will use both guided and special ammo... AHEAD type rounds and guided shells and shells using the equivalent of AINET... they have developed the latter for 30mm cannon shells so one for a 57mm shells should be easier and cheaper and more accurate... making it more effective.

Of course, the rate of fire is measured in rounds per minute, but to create a fire wall only a few seconds are necessary. As example with a rate of fire of 500-1000 rounds per minute by barrel, a 57-4 configuration would fire 100-200 rounds in 3 seconds. And with todays control of fire you can fire just the amount of projectiles that you want for every target (50, 75,..).

If it is going to be firing 50 rounds at each target then it is a total waste of time.

A primary advantage of the 57mm is guided shells offering the ability to take on a large number of incoming threats... ie UCAVs and UAV targets... 50 rounds or even 10 rounds per target and you are wasting an enormous amount of ammo... it is like having to fire 10 rounds of 125mm ammo for a kill... or a chance of a kill.

Roughly, doing the calculus for a 0.057x0.057x0.30m3 by round (assuming a lenght of the cartridge of 30cm, it means 0.916m3. I think that would not be difficult to find 1m3 inside the kurganets platform to have all it inside.

Sorry... what?



In this image look at the size of the 30 x 165mm shell that is fourth from the left in the image above.

Now look at the round at the far right... the 35 x 228mm round... see how it is about 1/4 bigger than the 30mm round?




Now look at this image... the tiny round far left is the 35 x 228mm round, and the 57mm ammo we are talking about is second from the right... the 57 x 347SR.

Now that is the old 57mm round but the new round might be a sophisticated telescoped round, or it might not, but its primary requirement will be an APFSDS round that can penetrate enemy IFV armour at battlefield ranges so the case might be even bigger than this to get the velocity and shell capacity needed for the jobs it will be used for.

I suspect they might go for a telescoped case and certainly a semi rimmed or rimless case, but I suspect bigger but better shaped to make it easier to use in automatic ammo handling systems.

the IFV will have about 300-350 rounds at most and the SPAAG will likely have maybe double that at 600 rounds... but with a very large percentage guided shells for the SPAAG and perhaps half to a quarter of the ammo for the IFV which will have more APFSDS rounds and HCHE shells for battlefield targets.

Garry B, the calculus about volume is very basic but is well done. I have not trouble to explain it.

0.057m=57mm
0.3m=300mm

m=meter
mm=milimeter
m3=cubic meter

0.057x0.057x0.3m3 is the volume of a prisma with a square basis of 57mm of side, and height of 300mm. This prisma is able to include inside every round of 57mm with 300mm or less of lenght. It is an approximation to the volune of one projectile of 57mm by excess.

0.057x0.057x0.3x940=0.916m3 is an approximation by excess of the volume of 940 projectiles of 57x300.

For ammunition of 57x350mm it would be:

0.057x0.057x0.35x940=1.069m3

Well part of the problem is that a 57mm round is not a rectangle shape and will not fit inside the rectangle shape you describe.

The 57mm shell is more like 80mm square due to the shell case being a rather larger calibre than the projectile which you are using as a basis.

A comparison would be to describe the 5.56mm NATO round as being 5.56mm square and 45mm long... it is clearly not either of those things.

The 57 x 347mm dimensions of the round describe the diameter of the projectile (57mm) and the length of the shell case (347mm). That totally ignores the diameter of the whole round... ie the shell case and also the added length of the projectile that adds to the length of the entire round of ammo.

The length of the entire round is 536mm for the navy 57mm shell and looking at the photo I posted above the shell case diameter is more like 80mm using the calibre of the 40mm round sitting next to it.

Assuming no belt mechanism between rounds in the ammo handling system that would be needed to move the rounds from the ammo mag to the gun to fire the rounds then we are talking about 80mm square rectangles that are .54m long... so .08 x .08 x .54 x 940 = which is more like 3.2 cubic metres... and that is without the ammo handling system to move them to the gun and load them...

BTW 940 rounds would be just under 6 tons in weight too...

300 rd/minute ,thats 5 rds / sec. just 1 sec burst - 5 guided rounds should make 100% certain kill on any target within 6km.
usually laser gets rounds close to the target ,then proximity radio fuse in the round does the rest ,so you dont have to make a contact every time to achieve a kill.

exactly... 300rpm is actually wastefully high...

80mm cases for 57mm ammunition? Sincerly, if a case of 80mm is needed, better to make it 76mm ammunition. This is what has been done the last decades. For calibers of this size or bigger, I only see cases with a 40% plus of diameter in ammunition of 50+ years old (maybe 60+).

For anti armour and anti aircraft use a large shell case provides lots of propellant... which is needed for high velocity.

You can make it a 76mm round but then the performance of the APFSDS round will be pathetic and its surface to air performance will also be mediocre.

The shell case capacity is what gives it the volume to allow for long rounds of guided projectiles while still having space for propellant to make it useful.

But even 3m3 seems not too much in a platform that allows to move 8 passengers (+3 of the crew).

3 cubic metres is shells only... it does not include the mechanism for loading and moving the ammo from where it is stored to the gun.

The calculus of this approximation it is not the configuration for minimum space storage, only it is an easy and useful approximation.

I know. The real space requirement is much much bigger...

It is curious to me to see how you was not able to understand the easy calculus at the first moment, which obviously means that you have low mathematical skills, and still you are assuring that "the real space requirement is much much bigger". It is amazing coming from a person that is not able to identify the volume of a prisma, and that is not fluent with the use of the units of the SI.

I understand your method, just your application baffled me.

To put it in terms of small arms ammo what you were saying is that a 7.62x39mm cartridge should stack perfectly vertically and assuming 7.62mm square with a length of 39mm then the volume of an AK magazine must be 39mm long, 7.62mm wide and 7.62 x 30 tall... and I will give you a hint... an AK mag is rather larger because it has walls to contain ammo, and the spring used to push the rounds up into the mechanism into the rifle makes the magazine longer. More importantly the sides of the round are not parallel so the magazine has to be curved, and of course the biggest problem is that AK rounds are not 39mm long.

BTW the term prism generally applies to an object used to refract light and has a triangular cross section.

Let me see one model of ammunition over 50mm designed by the Soviet Union/Russia after 1970 that has a 40% bigger diameter in the case than the nominal measure of the ammunition.

What model of ammo over 50mm was developed after 1970 in the Soviet Union or Russia?

No, no ,no, I said clearly over 50mm, nothing about 7.62mm... you have a generous range of big calibers to find...

No there isn't a generous range of rounds developed after the 1970s in calibre larger than 50mm that are high velocity anti armour rounds.

there are low velocity 57mm grenades that have not entered service, there is the low velocity 100mm round designed for the BMP-3s 100mm rifled gun... and not much else.

The high velocity tank ammo in 125mm calibre are rather like telescoped ammo in that the primary propellent charge isn't larger calibre so it can be stored in the same compartments as the ammo itself and the extra propellent is carried by wrapping it around the small calibre APFSDS projectile to get the velocity needed.

AFAIK the 57mm ammo being used for the new vehicles as an anti armour and anti aircraft round is based on the 57mm round above, which competed with a telescoped 45mm round... which lost on the grounds that the smaller calibre round has a much more compact case so it had less room for guided and other special ammo.

This suggests that the new 57mm round likely has a similar shell case, though perhaps they will have made it fully semi rimmed and a more cylindrical case so the empty case can be ejected forward from the firing mechanism...

So you are not able to find a single model of ammunition over 50mm designed by the Soviet Union/Russia after 1970 that has a 40% bigger diameter in the case than the nominal measure of the ammunition.

I am not able to find a single model of ammunition over 50mm in calibre designed by the Soviet Union or Russia after 1970 that is designed to penetrate armour... ie high velocity ammo at all, let alone one with straight walled sides.

NOTE if you look at the cross section of the old 57mm shell with the guided round fitted the round actually fills the entire shell case back to the rear end... so if you made the shell 57mm in diameter then there would be no room at all for any propellant...

Again, like in the case of the rate of fire you are taking very old things as model of what can be done today, only because it was done this way in the 1950s.

And you seem to be under the belief that if something can be done it should be done... can you please explain why GPMGs don't fire much more than the 600rpm that medium machine guns fired at during WWI. Is it possibly that rate of fire is not that important against ground targets and is actually rather wasteful of ammo?

Just look at anti aircraft mounts of the Soviet Maxim MMG.... where a higher rate of fire was needed they simply created an anti aircraft mount that had four guns with one aiming sight fitted.

The other way would be to have a much higher rate of fire, which wastes ammo for most uses except anti aircraft use.

125mm
122mm
152mm
120mm
130mm
100mm
82mm
76mm
57mm
203mm
240mm

Nothing in any of those calibres has been developed since the 1970s...

even you can try with mrls rockets or everything else over 50mm you want...

122mm
220mm
300mm

Rockets don't have shell cases...

All the ammunition of 125mm used by the Russian tanks and anti-tank artillery, including high speed and antiarmor ammunition, has been designed after 1970...
Almost all the guided ammunition of all calibers used today has been designed after 1970...

125mm gun ammo uses a stub shell case and is considered caseless ammo.

It was first used in the T-64 tank in the mid 1960s. There have been variations of the gun produced since but no fundamental changes... and it is considered a caseless round using two part ammo.

No excuses... the casing of the ammunition of the biggest calibers designed at least in the last 45 years are of about the same diameter of the nominal measure of the ammunition, not a 40% bigger in diameter...

The only round that could possibly apply to is the 120mm western tank round... the others don't use conventional shell cases.

The 57mm round is based on the old round... if they reduce the diameter of the shell case to the diameter of the calibre then there wont be any room for propellant unless the rounds are a metre long.


Assuming a shell case that equals the diameter of the calibre is just dumb... in the competition the 45mm round was revealed to be a telescoped case round while the 57mm round was based on an existing round... the 57mm round was selected because the projectiles are larger and have more capacity for different payload types.

For the same reason during WWII the T-34 entered service with a medium pressure 76.2mm gun instead of the competition which was a high velocity 57mm gun with much better armour penetration performance. The 76.2mm gun had better penetration at longer ranges but had a much more effective HE shell.

I suspect the result was no different comparing the 45mm and 57mm rounds.

I actually think that the model shown of the BMPT based on armata with a 120mm smoothbore gun/mortar plus a 23mm 6 barrel gatling gun and a 40mm or 57mm long barrel grenade launcher would be the ideal armament for BMPT-3

In the past the vehicles used in the role have been anti aircraft guns with devastating instant fire power in 23mm or 30mm high rate of fire cannon... the vehicle I mention above can match that with the 23mm gatling alone... 10,000-12,000 rpm with a low velocity heavy projectile in a small compact round slightly bigger than HMG ammo... for other targets direct fire and also guided 120mm and 122mm rounds and missiles with low velocity 40mm or 57mm rounds offers an all round package of heavy HE fire power and direct fire and indirect fire weapons for a range of targets.

Regarding using two 57mm guns the weight and space to fit two guns does not really justify the moderate increase in rate of fire.

Each gun will likely fire at about 300 rpm so two guns you get 600rpm but a lot more vibration and recoil which would upset long range accuracy to the point of making it useless. 4 or 5 shells per second hitting a target in 57mm calibre would be devastating on their own... a single round direct hit with a guided shell would be even more devastating to most targets.

The size of the rounds means a standard HE shell could be fitted with a very accurate time fuse meaning a single round could be detonated amongst a group of enemy swarm UAVs damaging or destroying them all... tiny UAVs will be fragile little things remember...

the saving of removing the second 57mm gun means a weapon like a low velocity grenade launcher (57mm or 40mm) could be added to allow a much wider range of targets to be engaged with low velocity rounds... even a 23mm gatling... or even a twin barrel 30mm cannon or 23mm cannon.

I see a good number of comments deleted.

Not sure what you mean...

As I was defending here before the new, a 57-2 or a 57-4 configuration is logical. Russia will not waste an armata platform for only a 57mm weapon. If there is interest in this weapon, for sure the configuration used will not be weaker than what they did in the past, and the 57-2 was proved with the ZSU-57-2 a lot of decades ago.

The twin gun arrangement was used to maximise the rate of fire because having only rate of fire to hit a target that is manouvering means the more shots you can put up at a time the better your chances.

The guns use a four round clip so rate of fire is limited anyway.

In the case of an IFV or air defence (SPAAG) or indeed tank support (BMPT) vehicle version of of all the new vehicle families it makes sense to have just one gun and more ammo because dumb ammo and pure rate of fire wont make sense against very many standard targets.

Accuracy and guided shells are what make them valuable at battlefield ranges... which an extra barrel in the turret would reduce rather than improve.

To have guided ammunition, of course is a must, but also cheaper ammunition can be used like for other calibers.

It would be cheaper and easier to fire one or two guided shells than to plaster the area with dozens of shells to try to get a hit...

Curious though which ATGM's they may use in future? Hermes isn't out or tested yet.

Well Krisantema and Kornet-EM are in production and service... they also seem to be developing a new fire and forget model now too which would be interesting too...