180 km range is deep well enough into the enemy's rear. Whatever target you spotted that far off would have to be pretty important militarily if its to be engaged, enough to risk whatever asset has acquired them in the first place. If its that important it would also warrant a much stronger strike option than a mere artillery shell just to make sure whatever you hit stays dead, so an Iskander perhaps.
We know too little about the 180km range round to talk seriously about it... it might be a specialist round for artillery to be used with UAVs in situations like Syria where you can fire and the UAV spots the moving target for you and the round itself might have a 10kg payload and a rocket or ramjet motor with the rest of the weight fuel to get that far... not good for sinking ships but taking out small trucks and light vehicles or individual enemy positions like ATGM launchers or machine gun nests... with the guidance of course it would be excellent.
Or it might be a double length round with a normal payload and a ramjet motor at the rear with fuel tank and nose mounted optical guidance...
If the target is a bit stronger than a light vehicle it should be able to fire a dozen rounds at slightly different angles to ensure they all hit the target at the same time... which is always pretty devastating... note even 70km range shells are coming in from behind the horizon at sea level.
The smart fuzes with the small paddles? Those only work if the projectile is spinning at several hundred rpms - if not they would provide asymmetric drag and send the projectile into an uncontrolled tumble.
But that is the point... they don't want the HE rounds to spin... the spin of a rifled barrel just makes accuracy with satellite navigation systems more difficult to achieve.
My understanding is that the guidance system for standard rounds is based on a nose mounted fuse system that has a guidance package and control fins to steer the round in flight.
It has a slightly larger burst radius, but drastically slower rate of fire.
Slightly? 45kg for 152mm vs 110kg for 203mm calibre. 2.5 times heavier shell... not to mention greater range.
If you're engaging rather robust targets like a ship with not much armor to speak of its actually better to have a much higher rate of fire to rack up the hits and spread the damage over a wider area. And would you look at that, the smaller calibre 130 mm rifled gun for the Bereg is exactly what the doctor ordered.
Rate of fire for naval guns is not the same. Plus the 130mm gun has a range of less than 30km, while Coalition is already reaching more than double that with standard rounds...
Its acting penny wise and pound foolish - the turret gives you the supreme benefit of decoupling shooting from movement. In a fast paced armored brawl where engagements can start and end in literal seconds you'd want that capability with you than without.
With autoloader technology and no turret bustle a tank without a turret would have no practical limit on penetrator length... a projectile that could also be used in towed variants of the gun too...
An ambush vehicle with a rear facing gun with electric drive that can turn on the spot... with active suspension so it can elevate and depress the vehicle as well as the gun leading to super elevation and super depression angle potential.
Having a ten round dual feed autoloader means you can have two types of ammo ready to load and you can get ten shots off before moving and repositioning... though you would probably want to fire one or two quick shots and get your kill and then move.
Excellent defence gun... low and easy to hide, able to take advantages of reverse slopes and interesting positions.
Even just start with a 125mm gun and make it a gas turbine all electric test bed.
I wouldn't bother with a heavily armored turret at tall, and save on the trouble of hauling an extra 10 tons of dead weight.
You could have two models... one with a light weight T-14 like turret, and the other could be a fixed gun with an autoloader able to take all sorts of length penetrator rounds. It could have a towed gun twin mount for defensive positions.
The Armata chassis is not just a good base for armored fighting vehicles. The high strength hull can also be used as a prime mover for heavy equipment like strategic SAMs, heavy rocket artillery etc. It would be ridiculously expensive to buy and operate, but then again these capabilities are already expensive on their own that a little more splurging wouldn't really hurt that much more. Against a near peer threat that would require you to bust out the big guns you really don't want to exercise restraint - throw the kitchen sink if you have to, just make sure you win.
Only a country like Israel would go all Armata... that missile layout could go in the back of almost any vehicle type including Kurganets and even Boomerang and would be especially useful in the two chassis DT-30 arctic vehicle they are using.
That missile layout could be applied to current generation platforms too... BMP-4 BMD-4 BTR-82 MTLB etc etc.
The missile range means it does not need direct line of sight nor does it need to be on the front line, so mobility is probably more valuable than armour, and certainly C4IR is critical for it to be effective.
What's the need for 203mm rounds when Iskander already exists?
They have effectively doubled the range of the 152mm rounds and appear on the verge to extending them even further... using the same techniques and technologies if they could do the same to the 203mm round then they would have a relatively cheap mobile system for both land and sea use that could hit point targets out to very useful ranges freeing the Iskander up for more strategic targets.
These artillery rounds are free flight free fall ballistic rounds with simple minor steering to get them very close to the aim point... an SA-15 air defence missile could shoot them down easily... but the west does not have SA-15s and they don't have a huge number of SAMs to waste on artillery shells.
It means in serious WWIII combat they would have a long range (90-100km) weapon system accurate enough to hit an individual house and heavy enough to flatten half of it with one shot.
Being modern artillery a battery should be able to launch several rounds and time them so they all land together... which would actually be pretty devastating.
They can have millions of 203mm shells, but closer to thousands of Iskander rounds.
For naval artillery it will just reach further and hit harder than existing calibres and the cost of development can be shared with the Army.
Effectively, 18 ATacMS equals the impact of 792 155mm artillery rounds.
So each ATACMS has a warhead 44 times bigger than a 155mm round?
Hard to believe.
What I suspect is the case is that the accuracy of ATACMS means it hits the target in one shot, while conventional HE rounds require an average of 44 rounds to be fired for each target to ensure it is hit properly.
The difference is that the Russian Coalition 152mm shells have smart fuses with guidance kits included that steer the round onto the target so instead of firing a volley of shells at a target to ensure a hit and a kill it can fire 1-2 rounds to get the kill.
203mm rounds will use the same guidance but the shells are 2.5 times heavier.
Very good question but I would say the Iskander has a minimum range of around 50km - that is probably around the maximum range of the 203mm artillery piece.
Iskander will be focused on different targets, and I am not sure they would deploy 203mm guns in every unit. Currently 203mm guns and 240mm mortars are in service but are kept in reserve for situations where their special capabilities are useful.
For the Navy on the other hand a mix of 203mm and 152mm guns would be excellent for providing naval gunfire support to landing operations, but also for use with warning shots in anti piracy missions etc etc.... warning shots for British destroyers violating Russian waters.
Russia operates 203mm 2S7 for decades and is modernizing them right now.
70km is its actual maximal range, and the guns have their niche in Russian operational plans.
There is no point in discussing the need for having those.
I am talking about upgrading the 203mm the way they have upgraded the 152mm guns with Coalition... the costs could be shared between the Navy and Army... they already share SAMs for the most part, it would be good to unify the guns... they already both use 30 x 165mm and the 57mm gun calibre... the Army really does not need a 76.2mm calibre, and the 100mm calibre on land is becoming redundant too.