Reason that comes to my mind are space, the gatling guns kashtan/pantsir have but tor doesn't but also more fire solution during a salvo attack so more missile fired at the same time.
The reloading system for the missiles are what makes the system consume the volume of several decks below where it is mounted, but as shown with land based SAMs there is no reason why even multi stage missiles like the S-300V cannot be vertically launched in space efficient launch bins.
The long narrow physical shape of the Pantsir and Kashtan missiles means they would fill more space than the shorter smaller TOR missiles, but that length provides extra range and performance too.
Both tor and pantsir use one radar each so when engaging one target left another target on the righ can't be engaged.
Not true, but systems can actually control up to 8 missiles at a time against four targets with the field of view of the tracking radars which are quite wide... with four to 8 vehicles in each battery it is perfectly plausible to have each of the vehicles positioned to provide 360 degree coverage with their tracking radars... and both systems can optically engage targets too.
You need to destroy the first target and then turn your radar aquire the target, lock on and engage.
No you don't.... a battery is coordinated so perhaps lets say 6 incoming targets, three from the south, one from the west and two from the north, so one vehicle could engage all three targets arriving from the south at once with up to six missiles, while another vehicle can engage the targets from the north and another the target from the west.
The tracking radar can lock onto up to four targets at a time.
Pantsir has 20-0km range so it has the time to do so against a low numver of missiles, but kashtan with its 8km range missiles would be overwhelmed by 3 missiles.
Not at all.... in both cases the effective radar range extends well beyond the missiles engagement range so the Kashtan could be tracking the targets out to the same distance the Pantsir does and missiles could be launched as the targets approaches the 8km range... both sets of missiles are very high speed so interception would occur in less than 15 seconds, so 16 targets approaching, the first four could be shot down at about 8km and 20 seconds later then next four missiles could be launched and while those missiles are in flight the next 8 missiles are loaded onto the launch mount ready for 20 seconds later when the next four missiles can be launched.
Kashtan could shoot down rather large numbers of targets with missiles and guns when the targets are much closer.
Pantsir is the same.
Kashtan and Pantsir missiles move at about 1km per second and the newer missile versions are even faster.... the missile flight time to 8km is less than 8 seconds.
The missiles are command guided and can therefore can be re-directed to new targets when their initial target is shot down. The engagement time for each missile is rather short even for Pantsir at 20km range by the time the missile gets to the target it is still travelling at over half a kilometre a second... and missile reloads can be performed with missiles in flight.
That's why you want different level of air defence. For ships, agaibst anti ship missiles flying very low, you need medium range system (Shtil-1 or 9m96), then a short range system (tor) and a CIWS (pantsir).
With a good radar picture... either from a bigger ship or a Ka-31 AEW aircraft enemy anti ship missiles can be shot down at max missile range with Redut down to sea level... that is 60km for the small 9M96 missile and 150km for the bigger of the two. General information to get the missile to the target area and then the missile turns on its own radar and finishes the job.
I would even add a laser guided sosna-R or IR guided Igla mount in order to not depend 100% on electromagnetic guidance (radar/radio).
Would agree but would suggest the reverse is the most likely situation... the radio command guided TOR and Pantsir missiles offer day night and all weather capability for situations like sea fog and heavy rain where laser beam riding and IIR guided missiles have degraded performance.
Plus of course the command guided missiles are super cheap and very very accurate.
Long range like S-400 are useless against missiles flying very low against which detection range is around 50km. Could use it but it's better to have quad pack 9m96 instead of 48N6. What they are good at is keep the enemy air force far away to not let them come close to jamm your fire control radars or use smaller missiles in bigger number.
They both have their own radars being ARH missiles so as long as you can detect the targets at beyond the radar horizon then you can use them to engage them too.
Whether it is a Ka-31 AEW aircraft, or another ship, or a MiG-29K using its radar to detect incoming threats and passing the target data to the ship group.