PLAN test and experimental vessels

[AndrewS]

Although technically all current large calibre guns have dual roles capability in anti-surface and anti-air purpose, the slow rates of firing for 127mm/130mm and 155mm make them less effective against fast anti-ship missile vs the short range air defense missiles that cover the targets that are beyond the effective range of 57mm/76mm rounds.

The HQ-10 / RIM SAMs have a range of 9km

What about the gap from 9km to 20km (radar horizon) or 35km (sea skimmer detection range)

Cost of the air defense missiles vs gun rounds are not important compared to the cost of loosing a ship's operational capability if it is hit by an antiship missile. Rather, the effectiveness of protecting the ship at what affordable cost should be prioritized.

1. You could buy ten? guided 155mm rounds for the cost of a single RIM missile.

2. Plus the 155mm rounds have a much longer range, so can be used first and deal with the incoming missiles quicker and before they reach HQ-10 SAM range.

3. An Arleigh Burke has 680 artillery rounds for example. It isn't going to run out of rounds when being attacked. There are only 24 HQ-10 SAMs available for Chinese Destroyers.

4. You're going to have a main gun anyway. So why not go with a larger, more effective calibre that shouldn't take up much more space/weight

Therefore, the 155mm gun sighted in Dalian would be mainly used for hitting surface targets, though not losing anti-air capability (which is far less effective vs air defense missiles).

PLAN have their own thinking on how and when they are going to use this 155mm calibre gun, otherwise they would not have develop it.

Hitting enemy's non-missile armed ships is very obvious choice for using guns, example commercial ships and navy auxiliary ships. Targeting shore targets on Taiwan, Penghu, Jinmen and other small islands in South China Sea is feasible with long range guided rounds, especially after eliminating all known shore based anti-ship missile, and also after gaining air superiority over the sky above the shore.

Targeting moving land targets like trucks, SP guns, mobile radars, mobile missile carriers etc. can be very precise with aid of drones, which bring type 076 into the scenario. A 30km range normal round or an extended 50-100km+ range round can be fired from a ship sailing close by the shores of Mainland China, where the ship is protected by its own as well as land base air defense weapons. So, yes, hitting Taiwan island shore defense by 155mm gun is not only feasible but also very effective.

I'm not convinced, given that glide bombs and low-cost cruise missiles have much larger warheads and should be a lot cheaper than a long-range guided 155mm round.

 

[AndrewS]

@para80

Let's assume an incoming subsonic cruise missile is detected at 35km.

With a standard 155mm round, I get a ballpark intercept point at 20km (60 seconds).

At 10 rpm, that is up to six 155mm intercepts, before the first HQ-10 can possibly launch, with its first intercept point at 9km.

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Of course, with specialised, faster rounds, the 155mm can engage sooner and further away.

 

[Heliox]

It's not about firing rate. It's about the 155mm artillery round having more range and volume, so it can fit in a guidance system.

Agree. For surface targets, slower rate of fire is not too big an issue as well, a rule of thumb metric is comparing throw weight per minute where larger calibers compensate on slower ROF with much larger shells for a higher throw weight than many smaller, faster firing caibers. It also helps that larger shells have better terminal effects. ROF really only comes into play when you have short engagement windows - eg. Anti-Air and/or CIWS applications.

Volume wise, you can fit PG systems into 57mm (Northrop Grumman for MK110) and 76mm (Oto Vulcano). Volume is not really the issue.

the 76 mm Strales regularly getting emphasised as being very capable because of the sweet spot in RoF and ammo size.

The Oto 76mm STRALES is not in the same discussion. The STRALES is a guided submunition with typical engagements being 3-5 rounds fired. This is in stark contrast with unguided gun rounds needing to throw up hundreds of round quickly to form a "wall of lead" in a similar AA/CIWS situation.

What is the driving motivation then for 155mm?

Land attack with standard unguided 155mm artillery rounds seems like a very poor reason to develop a new, larger gun calibre.

And if you want to go with longer range and/or guided rounds, the cost balloons. So much so that they become much more expensive than glide bombs or low-cost cruise missiles which have much larger warheads.

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The Italian 76mm makes sense, if you assume that the ammunition is a low-cost unguided round, so you want to fire as many as possible. We can see the Italians prefer to use the 76mm over a Gun CIWS.

But in the past 10 years or so, electronics miniaturisation means artillery rounds can now be guided and also see drastically reduced costs compared to previously.

As above, the Italian Navy went with 76mm for CIWS not because of the rapid fire rate but because guided STRALES munition allowed for a novel method of performing CIWS with other than fast ROF gatlings. Also, probably because the Oto 76mm is the most widely deployed gun they (ITA/OTO) produce.

For all other purpose, the advantage of a bigger gun is primarily
i) better range without use of ER munition
ii) better terminal effect

If you are going to use a naval gun for gunfire support, you want to have as large a standoff distance as possible. Bringing a naval warship close to shore just to throw a few kilos of HE at a land target is risky - unless we're talking about some cheap bespoke purpose built ship (see @Wrought post prior).

Long range fire using unguided munitions is largely inaccurate and more for interdiction. So a large caliber gun for NGFS will need to have ER and PG rounds (again, unless purpose built cheap naval shore bombardment vessel)

So either we may see a scenario specific special vessel in the future (like the landing barges) or we may be seeing the start of a long term drive for commonality in calibers between land and sea artillery calibers(?)

@para80

Let's assume an incoming subsonic cruise missile is detected at 35km.

With a standard 155mm round, I get a ballpark intercept point at 20km (60 seconds).

At 10 rpm, that is up to six 155mm intercepts, before the first HQ-10 can possibly launch, with its first intercept point at 9km.

---

Of course, with specialised, faster rounds, the 155mm can engage sooner and further away.

Only works if the incoming flies straight and true. Any AShM with evasive terminal maneuvers will be near impossible to engage at range without guided munitions of some kind.

 

[Gloire_bb]

With a standard 155mm round, I get a ballpark intercept point at 20km (60 seconds).

Ugh, something is very wrong with math here.

Only works if the incoming flies straight and true. Any AShM with evasive terminal maneuvers will be near impossible to engage at range without guided munitions of some kind.

Why not guided munitions then? Ability to switch between multiple kinds of ammo at will is the strength of a gun with automatic ammo handling.

As above, the Italian Navy went with 76mm for CIWS not because of the rapid fire rate but because guided STRALES munition allowed for a novel method of performing CIWS with other than fast ROF gatlings.

It's not exclusive, and at shorter ranges existing strales becomes less effective than just prog AA HE.
Plus this isn't the only way of doing guided AA shell in the first place, for example US NG 2" one for mk110 doesn't constrain rate of fire, only rate of engagement (by need to verify results of engagements).

 

[Lethe]

Sometimes the simplest explanations are best: China just likes building and tinkering with things. It gives the engineers something to do and prevents them from wandering off to become accountants.

 

[AndrewS]

Ugh, something is very wrong with math here.

The AI agrees on about 60 seconds for 20km

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The time of flight for a 155mm shell to travel 20 km from an L52 howitzer is approximately 58 seconds. This may vary between 55 and 65 seconds depending on the specific charge zone and shell aerodynamics.

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Using standard ballistic tables for a 155mm projectile (like the DM121 or M795) fired from an L52 barrel:

At 15 km, the time of flight is approximately 40–45 seconds

At 20 km, the shell must maintain sufficient velocity to overcome drag, resulting in a flight time of approximately 58 seconds under standard conditions.

At 30 km (near the max range for standard rounds), the time increases to roughly 85–90 seconds.

 

[Gloire_bb]

The AI agrees on about 60 seconds for 20km

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The time of flight for a 155mm shell to travel 20 km from an L52 howitzer is approximately 58 seconds. This may vary between 55 and 65 seconds depending on the specific charge zone and shell aerodynamics.

Ah, sorry, then it's my mistake. I assumed you were talking about target speed.
For dead time, you can use

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gun for estimates; PLAN ultimately comes from Soviet naval gun tradition. This will add effective range (i.e. cut flight time) and flatten trajectories substantially.

It's possible, but largely pointless for naval gun to use land howi chamber and shell. Different design goals and priorities.

 

[AndrewS]

Agree. For surface targets, slower rate of fire is not too big an issue as well, a rule of thumb metric is comparing throw weight per minute where larger calibers compensate on slower ROF with much larger shells for a higher throw weight than many smaller, faster firing caibers. It also helps that larger shells have better terminal effects. ROF really only comes into play when you have short engagement windows - eg. Anti-Air and/or CIWS applications.

Volume wise, you can fit PG systems into 57mm (Northrop Grumman for MK110) and 76mm (Oto Vulcano). Volume is not really the issue.



The Oto 76mm STRALES is not in the same discussion. The STRALES is a guided submunition with typical engagements being 3-5 rounds fired. This is in stark contrast with unguided gun rounds needing to throw up hundreds of round quickly to form a "wall of lead" in a similar AA/CIWS situation.



As above, the Italian Navy went with 76mm for CIWS not because of the rapid fire rate but because guided STRALES munition allowed for a novel method of performing CIWS with other than fast ROF gatlings. Also, probably because the Oto 76mm is the most widely deployed gun they (ITA/OTO) produce.

For all other purpose, the advantage of a bigger gun is primarily
i) better range without use of ER munition
ii) better terminal effect

If you are going to use a naval gun for gunfire support, you want to have as large a standoff distance as possible. Bringing a naval warship close to shore just to throw a few kilos of HE at a land target is risky - unless we're talking about some cheap bespoke purpose built ship (see @Wrought post prior).

Long range fire using unguided munitions is largely inaccurate and more for interdiction. So a large caliber gun for NGFS will need to have ER and PG rounds (again, unless purpose built cheap naval shore bombardment vessel)

So either we may see a scenario specific special vessel in the future (like the landing barges) or we may be seeing the start of a long term drive for commonality in calibers between land and sea artillery calibers(?)


Only works if the incoming flies straight and true. Any AShM with evasive terminal maneuvers will be near impossible to engage at range without guided munitions of some kind.

Are the 76mm Strales DART rounds really just 20K euros each?

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At 20km, guided 155mm rounds are a given.

 

[AndrewS]

.

It's not exclusive, and at shorter ranges existing strales becomes less effective than just prog AA HE.

Plus this isn't the only way of doing guided AA shell in the first place, for example US NG 2" one for mk110 doesn't constrain rate of fire, only rate of engagement (by need to verify results of engagements).

Even at shorter ranges, guided rounds should still be better.

I think it would be close to 1 round for 1 hit, against a subsonic cruise missile.

(We see pK of 80% for guided SAMs against subsonic targets)

 

[Gloire_bb]

Even at shorter ranges, guided rounds should still be better.

It is more complicated. Strales in particular is single channel system - until target is confirmed down, channel is locked. HE PROG, esp. for simpler targets(such as drones) allows to proceed to next engagement immediately - either doing in concurrently, or alternate periods of engagement with observation to control results of previous engagements.