Re: new Chinese supertank,question....
RedMercury wrote:
Anyway, the experimental 120mm had 30cm accuracy at 2km with a muzzle velocity only slightly lower than the ZPT-98. This indicates that the shell was either relatively less massive (and still able to attain that kind of accuracy). Or, the gun has lots of muzzle energy and fires a relatively more massive shell, conferring the stability you discussed. Either way, I see no reason why the lessons from that sabot design, now 20 years old, is not incorporated into ZPT-98's sabots, if not further improved.
You speak of a gun being "overpowered", making it less accurate. I find this argument tenuous, because the ability to be "overpowered" means it can handle more barrel pressure, which also means it can certainly handle less barrel pressure. So there is nothing to stop the ZPT-98 from using less charge, bring the pressure back to "normal" (assuming your line of reasoning), and achieve comparable accuracy to the 120mm. Also, there's nothing stopping the development of a heavier, slower sabot which retains accuracy better (assuming your line of reasoning), or even a sabot that flies just as fast but is more stable.
To quote nemo from the Type98/99 thread:
So I still remain unconvinced there is anything fundamentally better in a 120mm than a 125mm. If anything, 125mm being "overpowered" means greater engineering leeway left for future upgrades, while the 120mm has all the performance already squeezed out of it.
As we have seen on the old Type 99 thread, the ZPT-98 has an even larger chamber than the 2A46M in order to propel the heavier IMI-Norinco APFSDS round; it would seem that the ZPT-98 may have reached the limits of the performance of the current 125 mm smoothbore. It is certainly an improvement, and if the figures on the old thread are correct, a dramatic improvement in AP performance has resulted out to some 2,000 m. However, as zraver in that same thread observed, there was a critical mismatch between the stated AP performance figures and the size of the chamber and the velocity of the round - something about either the size of the chamber or the mass of the round did not fit, and as such he doubted the stated AP performance figures.
Personally, I would argue that the performance figures are likely accurate, but were achieved by an increase in size of the chamber such that the round remained grossly overpowered for its mass, though the latter was significantly
increased over the original Russian round. A barrel life of 700 rounds (though a quantum leap over the paltry 100-round life of the Russian gun, but achieved by chrome-plating which the Russian gun originally lacked) indicates the continued
presence of a pressure-wave and the reaching of a critical velocity at the time of firing, thus degrading its accuracy. It also wears the muzzle quickly, degrading accuracy even if the barrel is otherwise serviceable; the
also has this problem, even though it's lower velocity than the 125 mm, and because of the use of the latest DU rounds, this has dropped barrel life from 400-500 to only 260 rounds - not good.
The excessive "shiver" generated by the detonation in such a large chamber travels up the barrel from the chamber to the muzzle at the moment of firing, knocking the muzzle out of alignment as it is overpowered; the 120 mm avoids this by opting for a slighly less powerful gun firing a substantially heavier round than either the Russian, Ukrainian, or Chinese-Israeli rounds. It's the 7mm Remington Magnum versus the .280 Ackley Improved bit again. Modestly decreasing the amount of propellant in the chamber would certainly increase accuracy and induce much less "shiver" during firing; the two questions then are: what AP performance is afforded by the projectile with the mass remaining the same?; and what increase in projectile mass can be achieved by reducing propellant in order to achieve greater AP performance?
As a related aside, India's DRDO has produced an improved
that is claimed to be able to defeat all NATO targets out to 2,500 m and over, and retain lethality out to 3,000m. This may indirectly indicate what the improved Chinese projectile is capable of. Depending upon what is meant by these figures (and especially "effective lethal range" at 3,000 m - this may or may not indicate a substantial degradation of either accuracy or penetration after 2,500 m), this may accord with the 2,500 m accurate range of the Ukrainian 125 mm and the 25% acurracy increase Tianren gave for the ZPT-98 over the original Russian 125 mm.
You cite the development of an ATGM to be evidence that the gun is not effective at 4 to 5km. I argue there are a whole host of reasons why you might want an ATGM with that range, even if you had a gun which was effective up to 4km. First, at 4km, your sabot will take 2+ seconds to reach the target. If it is a moving target, you'll need to predict accurately where it will be in 2+ seconds, something which is not easy to do on a moving and zigzagging tank, trying very hard to avoid your shot. With an ATGM, the missile has a much better chance of hitting a moving target, as long as you can guide it properly. Second, the ATGM can be used to engage attack helos (again, taking into account movement). Third, the ATGMs used by the PLA were imported/developed as a family, serving not only the ZTZ-99 but other AFVs, such as the older Type-59, ZTS-63A, ZBD-97, ZBD-2000, all of which are armed with weaker main guns.
Not exactly; ballistic computers have no problem dealing with moving targets, even while moving themselves, and they can calculate firing solutions for such situations without skipping a beat. Tianren's Blog post on the old Type 99 thread claimed the Type 99 was capable of an 85% first-round hit probability at 2,000m, rising to 90 or 95% on the second round. Not great, but good none the less, and if the same fire control system can guide an ATGM out to 4,000 m with ~80% hit probability, then it's no slouch. The Americans have been publicly claiming a 90 or 95% first round hit probability on the M1A1 at 3,000 m since the late '80s, and much the same claim is publicly made for the other 120 mm smoothbore-armed tanks.
provides a figures of 3,500 m accurate range for the Abrams and ranges of nearly 4,000 m attained in GW1; as I stated before,
The General's War by Gordon and Trainor states that there were kills made at nearly 3 miles by the M1A1.
Furthermore, red phosphorus-based anti-laser and anti-thermal smoke grenades interfere even more with laser-guided ATGM than with guns, as the smoke obscures thermal viewer and laser range finder for shell- and missile-launching tank alike. All the gun has to do it is get a range and firing solution, then fire; nothing the target tanks does after the projectile is fired will deflect it from its course. With the laser-guided ATGM, the target tank has to be acquired and then tracked all the while guiding the ATGM to the target; the smoke will easily deflect this attack, and the target tank change direction. The target tank has little, indeed insufficient time to change direction if a shell is travelling at twice the speed of sound towards it.
Zig-zagging was much more effective before the ballistic computers that came along by the late 1970's; now, with laser-range finders taking an instanteous ranging and ballistic computers calculating almost instanteous firing solutions, zig-zagging is much less effective than it was in the past, especially against shells, though missiles can still be more easily deflected by smoke obscuring either the laser (unless rear-mounted) and of course by obscuring the thermal sight's ability to locate and track through such smoke.
An ATGM with a HEAT warhead faces much the same AP limitations as HEAT shells at range, whilst requiring over 11-seconds to reach their targets at 4,000 m. As such, the firing tank is exposed for that length of time to the enemy while it guides the missile to its target. Only under favourable conditions can it take even a hull-down position while doing so, and a turret-down position not at all. By contrast, a tank firing a shell out to the same range can immediately lay on another target, or take up any position it desires except at the moment of firing (though even that may at least be a hull-down position), as it can immediately move back down into a turret-down position after it fires. And of course the shell arrives at its target in only a third of the time (at most) than it takes the missile.
An ATGM may have an advantage over a shell for anti-helicopter use, but that would depend upon the speed of the turret traverse in order to ensure the laser remained on the target - in which case, a shell may be a quicker way to despatch a helicopter than an ATGM, but an ATGM would have the advantage of a flatter trajectory in such a case, making it potentially easier to get a firing solution; it's a matter that is not entirely clear.
When Russian tanks fire their 125 mm, the
entire tank jerks and bucks like a bronco. The muzzle is knocked slightly out of alignment (as well as by the excessive "shiver" created by the over-powered gun), and the entire tank may actually shift its position on the ground slightly in some cases. Look at a Western tank; they do not buck like a bronco or even shift position sometimes when they fire. The gun recoils, but the muzzle is not knocked out of alignment. Newer Chinese tanks are heavier, and as such are more like their Western counterparts in that the entire tank will not shift its position, but the 125 mm gun still has its muzzle knocked slightly out of alignment from the excessive shiver created by the pressure wave of the detonation in the chamber.
Flank shots and destroying a T-55 do not indicate good armor penetration. Whether the 120mm can penetrate a current generation MBT armor from the front at those ranges remains doubtful. Being able to hit once (or a few times) without reporting how many tries it took tells me very little about the accuracy. Also, the tidbit about the Danes indicates that shooting at 4km is hardly standard practice for the majority of 120mm equipped armies, again casting doubt as to whether "accuracy" at this range is just dumb luck, or only made possible by very recent developments.
When an Army is conducting regular qualifications at 4,000 m it is most certainly not dumb luck, it's an outright training requirement that must be achieved, or gunners are stripped of their qualifications; if they don't make them up and qualify in good time, they are transferred to another position, or administratively disposed of - fired from the army. When an army uses this as standard practice, then it is certainly not an issue of just throwing scarce training time and dollars down a moneypit; unlike bureaucracies, unit commanders do not have the luxury of cost overruns. When the training funds run out, they run out, and depots will not release any resources to them without the money up front. The Danes are presently using the L/44 120 mm, but may upgrade to the new L/55 in the future.
Considering that the M1A1 was taking out T-72s in the flank at ranges approaching 4,800 m in GW 1, and the Challenger 1 took out the T-55 at
m in the same war - back in '91, it is not a recent technological development that has made this possible, though certainly improvements have since been made. Rather, it has been a case of recognizing just what the 120 mm smoothbore and rifle are really capable of. Until then, most training with the 105 mm has assumed a max range on the move (or even just stationary depending upon stabilization and fire-control) of some 2,000-2,400 m, usually without laser-range finders, though often with Low-Light Television (LLTV) by the late 1970's and 1980's. When laser-range finders, thermal sights, and DU ammo became widespread in the 1980's, when coupled to existing guns and especially the new 120 mm smoothbore, all sorts of possibilities began to be realized (although DU has proven more trouble than it's worth and the newer tungsten carbide rounds are more or less as good).
Dan Bolger (now an Major-General) back in the 1980's wrote in
Dragons at War: Land Battle in the Desert about how even then the M60A3 TTS was "rumoured to be able to hit out to 5,000 m against stationary targets". That of course was with the 105 mm rifle, and at the time, the M60A3 TTS had a better fire-control system than the M1 with the 105 rifle - a situation corrected in the 120 mm versions of the M1.
That said, you are quite correct to say that there is some doubt about the effectiveness of head-on shots on composite-armour (or equivalent ERA) tanks at such ranges, and I certainly agree with you there. The M1A1 were taking flank shots on the T-72s in '91 because the latter were advancing north across the former's front towards Basra; but those T-72s did not possess composite armour or ERA, and would likely have fallen to HEAT rounds even if confronted head-on at the same ranges. Sabot's great out to medium-ranges, but HEAT or HESH has to be used at long-range, and of course neither can penetrate the best composite armour in many cases. The T-55 was struck with a HESH round at 5,100 m by a Challenger 1 in '91, and it would not have made a difference whether the T-55 was head-on or not or even if it was an export-model T-72 for that matter - it would have perished anyway, as HESH simply dislodges the interior surfaces and components of the target and kills the crew inside, as well as setting off any exposed ammunition. Only composite armour is a clear defence against HESH, as even ERA appears to be stripped away by HESH, though ERA will probably stop or mitigate most HEAT rounds.
Current ballistic computers don't have any problem with moving targets; Tianren's Blog post mentioned that Type 99's fire control system could see out to ~7,000 m, track targets at 4,000 m, and identify them at 3, 000, and have an 85% first-round hit on a moviung target while the Type 99 is moving itself at 2,000 m, rising to 95% on the second shot; and it can guide the ATGM out to 4,000 m with ~80% hit probability - so while not great, it's still good. The Americans have claimed a 90 or 95% first-round hit probability out to 3,000 m on the move on the M1A1 (M1A2 has some problems that should be corrected by SEP) - that's great, and using a HEAT round, should have no problem hitting targets on the move at ~4,000 m, though with a substantially lower accuracy rate on the first round.
Admittedly, the recent Pakistani purchase of newer model Chinese tanks saw the Pak Army go with a French fire-control system in lieu of the Chinese system. First-round hit probability should be increased, but it is unclear how much range will be increased as well.
A 120 mm rifle would surpass this, especially with the new L-30 high-pressure rifle and the excellent fire control system on the Challenger 2 (as opposed to the old L-11 120 mm rifle and fire control system on the Challenger 1 that pulled off the 5,100 m kill); it's anyone's guess as to what the Challenger 2 is really capable of, though the Indians were claiming 4,600 m for the Arjun with a similar 120 mm rifle - but that tank has met an inglorious fate. Similarly, the new L/55 120 mm smoothbore that the Germans have produced for Leo 2A6 raises questions about its true performance. The new 120 mm smoothbore that the PLA has mounted on the Type 89 tank destroyer is claimed accurate through 2,000 m; that figure is most likely to be an understatement, obviously, if it supposed to provide long-range AT support to tank units. As such this would appear, given the continued use of ATGM by the latest PLA tanks out to 4,000-5,000 m, to be a second tacit admission that the 125 mm is somewhat lacking in long-range AP performance. Why resort to either, let alone both, if the 125 mm is perfectly capable of handling the long-range AT role that the 120 mm does with just shells alone? It makes no sense.
Overall, I would say that a new PLA "supertank" should carry a rifle; if the Russians are going to a 135 mm gun on their next expected tank, and the Americans continue to mull a 140 mm, the PLA should at least consider a gun of comparable performance, though not necessarily calibre. A long-calibre rifle of at least 120 mm, preferably somewhat larger, in a composite-armoured vehicle with diesel propulsion and wide tracks might be best for the Armoured Formations. A rifle has longer, more accurate range firing shells than a smoothbore, and it can use HESH aginst both field fortifications and long-range tank targets beyond the effective range of sabot (except against composite armour along the frontal arc). HEAT is less useful in a rifle because of the spin imparted to the round by the rifling, but is ideal in a smoothbore, though it cannot use HESH because it cannot impart a spin to it. Overall, HESH is probably better than HEAT for most purposes, and Smoke, Canister, HE-FRAG, HE, and APFSDS can be used by either gun.
As to an ATGM, like AT-11 or the developing US MRM, the former is probably unnecessary really, but the latter might be useful. That said, it is unlikely that either a rifle could launch an ATGM without reducing its effectiveness, or even that such ATGMs would not be better used by dedicated AT units providing ultra-long range AT support to Armour units, but then maybe a tank should have a few ultra-long range ATGM. It's certainly debatable.
Troika wrote:
Excuse me. I highlighted for reference, but I am not aware of PLA 120mm rifles. I know of indigenously developed 120mm
smoothbore mounted on Type-59 tank and Type-89 tank destroyer... and I know of the L7 clone PLA has, a 105mm rifle.
But not the 120mm rifle. I dug up the refernce,
post 54 on the T-80 thread by Crobato, stating that it is 120mm rifle from Oerlikon, claim that it was fitted on T-59 and type 89, and included was two very interesting pictures.
Now, what I want to ask is the source of this... I didn't even KNOW Oerlikon has a 120mm rifle.
Sorry Troika, I didn't mean to cause confusion here; I meant that the PLA had its own capacity to produce a 120 mm rifle, under license from Oerlikon since the 1980's. I apologize for my sloppiness.
