Unless the target is in the air, I think a Gatling weapon is pointless.
Normally I would agree... gatlings are very good at what they do but have a very limited range of very specific uses... which in the Russian military are for naval use against very high speed high threat targets where their rate of fire gives them a better chance of getting a few solid hits in the short time the target is within range. In their air applications they are for very small elusive targets like cruise missiles for the Mig-31, or for very short bursts at ground targets as they whiz by from high speed low flying aircraft... Su-24 and Mig-27.
The anti aircraft weapons on heavy aircraft tend to be twin barrel 23mm cannon because of their high rate of fire and heavy shell weight, while for ground attack it is similar with the Su-25 and Mi-24 carrying fixed twin barrel 30mm cannon with the latest model hind equipped with a twin barrel 23mm gun.
I agree that a gatling for an air defence vehicle is not a great idea because their twin barrel guns are so good that a couple of them on Pantsir-S1 or Tunguska offer better accuracy and comparable rates of fire.
The thing is that the BMPT can't really afford the room for two 30mm twin barrel cannon and the 30 x 165mm ammo is very very powerful but it is also huge.
The BMPT is not an air defence vehicle... it is an overwhelm them with firepower anti ambush vehicle and if you look at the vehicle it is replacing in that role.. the Shilka then a gatling makes sense... a GSH-5-23M gatling in particular.
The reasons are that it is a compact and simple weapon that weighs less than a single 2A42. It only weighs 73kgs and does not require an external power source like an electric drive like western gatlings. The ammo it fires is as powerful as the ammo the Shilka fires because the projectiles are identical... the difference is that it uses a much smaller shell case with less powder that generates a muzzle velocity of about 715m/s, but the point is that against ground targets that the BMPT will be engaging there is no need for high velocity anyway.
The compact nature of the weapon and the ammo itself means larger amounts of ammo will be able to be carried than with a more powerful weapon. The 23 x 115mm round is devastatingly effective against unarmoured aerial targets, it is the same round fired by the Mig-23s twin barrel 23mm cannon which was reportedly considered very accurate by South African pilots when they got a chance to test one out. The 23 x 152mm round the Shilka fires has a much higher velocity, which is necessary for intercepting high speed aerial targets but unimportant for ground targets.
The custom designed gun for the Apache is a case in point... very heavy 30mm projectile with a small shell case to allow large numbers of rounds to be carried. Very effective against ground targets... and includes a shaped charge round for anti armour use.
The vehicle does not need the sort of insane Rate of Fire that Gatling weapons produce, and the extra weight from the gun barrels, the volume that the weapon occupies, the recoil (yes a tank can take a 125mm gun's recoil, but the smaller caliber gun is often mounted in a less rigid spot), and most importantly the sort of ammunition storage you need for such a weapon, I think make it a very poor concept for Armata.
Fired continuously I would agree, but I rather suspect this weapon will have a burst management system in place so you can fire 5,10,15,20,25,30,40,50, or 100 round bursts only. The high rate of fire will mean the rounds land together in a sort of cluster bomb effect. Otherwise your criticisms have already been answered... the 23mm gatling is lighter than any 30mm cannon except the GSH-301 single barrel cannon of the Mig-29/Su-27 and is only 13 kgs heavier than a 12.7mm four barrel gatling gun used on the Hind. The weapon is light, compact and requires no external power source... it is pneumatic powered, recoil is low because of the low muzzle velocity and small charge... though recoil would certainly build up with very long bursts this gun is for hitting an area with HE, not chasing an aerial target in the sky till you hit it. The ammo is slightly bigger than 12.7mm HNG ammo so storing 800-1,000 rounds should not be that big a deal.
I say it again I generally agree with your criticisms... but in this case they don't apply.
The Vulcan has been used as an air defence vehicle by the US military since the Vietnam war and as an anti convoy weapon it was excellent. As an anti aircraft weapon however they are best used up close in a dogfight and lack range and accuracy to be useful as an AD gun.
Well S-400 will definitely be available for export, and (with some downgrading) I imagine Armata will be as well.
I agree but suspect the same problems with exporting the S-400... for the next 5 years or so domestic production will be a full capacity for the local market so don't expect to get an export S-400 till 2017 and don't expect an export Armata till after 2020.
I have a feeling a lot of Armata's technology will be offered as potential upgrades with the T-90MS, which is already a top of the line MBT. Armata might just end up being to costly to purchase in small numbers unless countries like India want a significant amount of them for their military and UAZ starts cranking them out like T-34's.
Agree with that too, certain features and components might find their way to T-90 upgrades which would be available for export, though it might turn out the other way where T-90SM bits and bobs are on exported armatas initially because the original equipment is not allowed to be exported yet.
Of course that raises the other question... what exactly will they export?
The armata concept basically requires a whole family of netcentric vehicles and a C4IR system supporting its operation... now a few bits of that jigsaw puzzle might not be for sale at any price for the time being... the real question is, when the Russians are ready to export it will the customer want an Armata based tank and a Kurganets based BMP and a Boomerang-25 based BTR and a boomerang-10 based BRDM type vehicle, or will they want the full mix of heavy, medium and light brigades.
For many countries they wont want the heavy brigades as they will be expensive to buy and operate. A mix of Kurganets and Boomerang in a medium weight brigade structure might actually suit a customer best as both vehicle types are amphibious and well armoured and should be well armed with excellent optics and communications and data linking capability, as well as modern passive and active modular armour.
In some back waters a 25 ton Kurganets with the afghanistan APS that can shoot down APFSDS rounds and a powerful 125mm gun with long penetrators and advanced thermal imagers etc etc would be a match for many previous generation MBTs. In fact the Kurganets IFV with a 45mm high velocity gun would probably be a match against T-62 and early T-72 and M60 and Leopard I type vehicles.