DU is special in how readily and the extent at which it self-sharpens. There are modern WHA alloys that can exhibit self-sharpening, but afaik none come close to the self-sharpening exhibited by DU.
Can't be that special if the difference in penetration is only 10%... imagine the difference in penetration between the blunt end of a pencil and the sharpened end of a pencil... as weak as at human strength levels you could push a sharpened pencil through flesh through an arm or a hand easily enough just using bodyweight pressure and being careful no to shear off the tip and make it blunt, while pushing the blunt end of a pencil through anything would take rather more force all round.
And that is just the concentration of pressure and clearly does not take into account the integrity of the material penetrator... too hard or too soft it might shatter or break...
The real irony is that at the speeds and energies we are talking about most metals act like fluids anyway, but of course the air is the problem... on the moon with no air to slow things down you could really use speed to your advantage.... at 20km per second it no longer matters what materials you are using.... 5kgs of chalk and 5kgs of chicken feathers, it is still 5kgs and at 20km per second both projectiles will vapourise anyway.
On satellite protection systems that means you use layers... a 5mm plate will cause any paint chip sized impactor to vapourise so a 50cm gap and then another 5mm plate will disperse the vapour and render it harmless... in comparison even a 50mm thick plate of Aluminium wont stop that paint chip and the volume of the material from that impact will act as shrapnel and destroy components throughout the satellite because of their volume.
Why? HEAT shells are less effective compared subcaliber shots for anti-armor use. If you really want HEAT to be viable against MBTs there's always top attack. Even a 125 mm tandem shaped charge is more than enough for multilayer roof armor.
HEAT performance massively increases with diameter... it is not an accident that Hellfire is a 152mm calibre missile, nor that the most powerful disposable Soviet/Russian RPG is a 125mm RPG-28...
A 152mm HEAT round does not need much in the way of propulsion as it can be all seeker and warheads... traditionally aerodynamically the nose should be pointy... with such a shape there is a 125mm HEAT round with three HEAT warheads to maximise penetration including a small nose mounted precursor charge to defeat ERA or NERA and prepare the surface for two full calibre HEAT warhead penetrations to come.
Of course if the round is top attack then why bother with 152mm calibre penetrations... a roof penetrator could be 70mm or less in calibre, and of course a bundle of four or five Bulat like missiles could be loaded into one 152mm HEAT round, that could be launched in the direction of enemy armour... the Armata drone might be marking 5 separate targets from enemy armour to enemy drones in any combination with the bundle of missiles each selecting its own target and engaging that target... a single HEAT round with multiple warheads to maximise penetration could be used against hard structures like buildings or several light vehicles in a row... another advantage of the calibre would be gun barrel launched missiles or drones which might use ramjet or scramjet propulsion and have enormous speed and range... a kinetic drone that is designed for impacts against very light structures like enemy light drones might be able to fly around for hours ramming through enemy small drones and destroying them simply though impact at mach 1.5 plus speeds... it would not need to be super fast...
But 5 km or more LOS at surface level is pretty rare outside of featureless deserts. The flight time also makes unguided projectiles impractical against moving targets - so you're going to be firing guided missiles. But if you're firing missiles, why not make them top attack and bypass the steep penetration requirements altogether?
Actually in mountains you can generally see rather further than you can shoot leading to weapons like grenade launchers and auto cannon and artillery to become rather useful. Being on the side of a mountain and seeing an enemy group on a nearby mountain 8-10km away can be quite frustrating as you don't often have much you can use to deal with them... way out of small arms and HMG range and also beyond 82mm and many 120mm mortar range and even 23mm cannon fire range... a T-62 or T-55 dug in to the ground with ammo stacked up near it was useful however.
As optics improve and net centricness expands, the chances that the platform firing the munition does not directly see the target it is shooting at becomes rather higher... and guidance doesn't need to be super elaborate... a simple laser target mark detector or optics for moving target detection or laser spot detector would be cheap enough yet at the same time allow attacking moving targets.
I didn't say that. But there is such a thing as too large a caliber.
I can agree with that, increasing calibre is a significant escalation that leads to problems like heavier ammo and more recoil, all of which creates negative effects like fewer rounds available for use because of the larger ammo, and of course problems with firing on the move etc, but you were suggesting that going from 125mm to 152mm would not be efficient because the larger calibre gun would still use similar sized penetrators and therefore the sabot would be bigger and less efficient, which is not really the case. The extra size and weight and drag of a sabot is nothing compared with the loss of muzzle velocity of having a sabot that does not fill the barrel and lets gas blow past the round.
Maintaining everything else a 152 mm sabot is nearly 50% larger than a 125 mm sabot. 50% larger is 50% heavier, for no reason at all:
Increasing the barrel calibre increases the amount of energy you can get from any particular propellent charge. A sabot that does not fill the barrel is not a sabot any more.
A Sabot is made of very light materials and is in comparison to the calibre of the round mostly empty space with a small structure that supports the penetrator and fills the gap between the barrel and the penetrator to prevent propellent gas blowing past as you know... a 1kg sabot for a 125mm gun and a 2kg sabot for a 152mm gun does not mean the 152mm round is useless or inefficient.
If both carry the penetrator down the barrel and release it at full velocity it will have done its job... the parasitic drag from the larger sabot will be higher, but the bigger heavier 152mm penetrator will still be vastly better than the 125mm penetrator... all other things being equal.
the effectiveness of subcaliber shafts is measured roughly by how long they are and how fast they hit the target. The sabot is entirely wasted energy.
That is right, but the larger calibre allows more energy to be pushed down that barrel for a given propellent charge, which is why subcalibre projectiles in sabot rounds are so effective.
If you're hitting from the top a 30 kg HE warhead is more than enough. Krasnopol hits with 11 kg HEF warheads but it demolishes any MBT it touches.
Which is why I was saying a 5kg penetrator in the first place because top attack means hitting the weakest armour...
Are there any changes in the Armata project? There is an article in The Moscow Times That I understand from it that the money for any project will be determinate by the needs for the fight in Ukraine. IS it going to effect the Armata project?
The Russian Army will almost certainly use lessons from this conflict and others in their design of the Armata vehicle family.... including but not limited to the T-14 tank, but I wouldn't pay any attention to the Moscow Times because it is a foreign owned anti Russia anti Putin anti Russian Army rag... left free at bus stations and doctors offices... no one pays for it... it is a propaganda magazine dedicated to destroying Russia.