125 mm gun out dated?

[dabrownguy]

Is the 125 mm gun outdated now. Because I've heard the Russians were moving onto larger barrels. Does this mean the 125 even with DU rounds is insuffecent? The other question is what is the penetration difference between the best 125 mm gun ie either Russian or Chinese and 120 mm german gun?

 

[Musashi_kenshin]

I don't think that the size of the barrel is that important - it's the quality of the weapon as a whole. You could have an inaccurate, unreliable larger gun, compared to a well-constructed 125 mm. It's best to look at the whole package in my opinion.

I have no idea about the second question.

 

[aaaditya]

most western gun are 120mm in calibre and yet are amongst the best in the world they may be of smaller calibre but they have a higher muzzle velocity and a higher barrel life.

 

[Aussie Digger]

The penetration range of a tank gun depends on the ammunition used, not the calibre of the gun. I'm not aware of the specific penetration characteristics for each gun, (with the different ammunitions types available) however I am aware that "Western" 120mm gun types consistently out ranged 125mm guns of Iraqi T-72's in both Gulf Wars...

 

[Pathfinder-X]

Two factors determine the penetration depth of main tank guns. One is muzzle velocity while the other one is ammunition. Russian tank guns generally does not have the same muzzle velocity that western tank guns have. One interesting thing to note is that the Chinese 125mm gun is actually based on their 120mm anti-tank gun developed in the 80's rather than Russian design.

In the scenario mentioned by AD, Iraqi T-72s were a downgraded or what grunts called "Pussified" version of the T-72s that Soviets at the time operates. I doubt coalition forces would have such high success if the "real" T-72 were deployed by the Iraqis. But then again, the Iraqis had no will to fight and were being pounded constantly from the air in the first Gulf War.

 

[boylde]

If you have a small army Budget you need something to fill the Gap till newer types become cheaper and if at war you may not be able to get Ammunation for the larger types and smaller may be easy to produce

 

[Revenant]

It's quite obvious that a tank gun of larger caliber will be more effective than smaller one (as long as it is a technically successful design) .The best example is a comparison between western 105 and 120mm tank guns.
When we talk about tank cannons we have to remember that its effectiveness depends on many factors:
- gun construction
- gun caliber
- ammunition quality
- FCS of a specific tank
When all mentioned conditions are fullfilled, than we can talk about effective gun design.
It's important to know that there is no such thing like 'Russian 125mm gun'. It's the whole family of 125mm tank guns which development took many years. So you can't compare 2A46/M cannons from T-72/M/M1 tanks with 2A46M-4 cannons from T-80UM and T-90 because despite the same caliber and similar names they are completely different designs.
Referring to the question about the effectiveness of 120mm cannons firing DU/tungsten ammunition, German DM53 (LKE II) APFSDS round can pierce through the 650mm of RHA (Rh120/L44 gun) and ~700mm of RHA (Rh120/L55 gun) from the distance of 2km. And Russian T-90 MBT frontal turret armour is able to withstand the hit of a APFSDS projectile capable of piercing 700mmRHA from 1km.
152mm tank gun would also have great antitank capabilities when firing HEAT rounds. Remember that 152mm is also the diameter of Kornet ATGM. I wonder if it's only a coincidence.
There is one quite big obstacle in coming guns of a new caliber into military service. It's the cost of a ammunition replecement. There are big ammounts of 125 and 120mm ammunition. That's why Western tanks still have 120mm cannons and Russian 125mm ones. Although Rheinmetall developed 140mm tank gun some time ago. There were also some information that the tank cannon of the same caliber was developed in the Soviet Union. Although it has never been displayed.
Nethertheless I belive that Russian prototypes, Object/Item 640 and T-95 could be (and probably are) armed with 152mm tank guns.

 

[gf0012-aust]

The principle reason why 140mm and 152mm calibre weapons have been unsuccessful is because of the following:

1) Recoil
2) Platform stability
3) Silhouette issues
4) Platform load out limitations

btw, the German 120mm has a far greater penetration rate than stated - I worked on a ballistics project approx 4 years ago involving Leo2 upgrades - 650mm RHA is ultra conservative - and I witnessed live firings.

 

[Revenant]

The principle reason why 140mm and 152mm calibre weapons have been unsuccessful is because of the following:

1) Recoil
2) Platform stability
3) Silhouette issues
4) Platform load out limitations

Well, apparently all those obstacles were overcome by UWZ during developing T-95. According to the available data T-95 weights ~50 tons. Of course Russian tank, mostly thanks to its turret construction, isn't overweighted and must be rather stable during firing. I only wonder if Black Eagle form Omsk is really equiped with 152mm gun. But on the other hand modern self propelled 152/155mm howitzers have no problem with stability although their centre of gravity is located much higher than in tanks.
I am also curious why Russians decided to use 152mm tank cannon, because it is known that it's possible to use even 50% stronger charges with 2A46M-4 125mm gun than those which are in use.

btw, the German 120mm has a far greater penetration rate than stated - I worked on a ballistics project approx 4 years ago involving Leo2 upgrades - 650mm RHA is ultra conservative - and I witnessed live firings.

I've got some questions, as long as it isn't confidential, of course. What type of APFSDS rounds were fired during those test you witnessed? And how much the achived penetration results were better from 'official' ones?

Best regards!!!

 

[gf0012-aust]

Well, apparently all those obstacles were overcome by UWZ during developing T-95. According to the available data T-95 weights ~50 tons. Of course Russian tank, mostly thanks to its turret construction, isn't overweighted and must be rather stable during firing. I only wonder if Black Eagle form Omsk is really equiped with 152mm gun. But on the other hand modern self propelled 152/155mm howitzers have no problem with stability although their centre of gravity is located much higher than in tanks.
I am also curious why Russians decided to use 152mm tank cannon, because it is known that it's possible to use even 50% stronger charges with 2A46M-4 125mm gun than those which are in use.

I'm really sceptical about the Russian figures released into the public domain on platform weight (+/- 50 tonnes)

A 120mm weapon exerts a minimum of 15 tons of recoil, a 140mm - 152mm weapon exerts exponentially greater tonnage. The platform movement is significant. Remember also that a SPG/SPH is designed to absorb recoil alomg it's axis at length which is thus better able to absorb the effect. Trying to achieve the same level of absorption at all arcs of fire and elevation, (and on the move) is a very very different exercise.

Bear in mind also that in the early years of development, the Russians went to a larger calibre weapon as they could achieve the same performance levels as the L7 heritage guns. ie it was an exercise in overmatching. Russian metallurgy was just not as good as that achived by Rheinmetal. This became apparent when the US managed to obtain access to 120-125mm platforms and pulled them apart for analysis.

There are more efficiencies to be gained from improving the round or shot used than there are in lifting the calibre. Logistically, there is not a lot of benefit in going to a larger round either. Your load out is reduced (especially on a smaller tonnage platform) You either start trading off on loadout - defensive armour etc... or you lose mission flexibility. The design intrusion into the crew compartment is significant

I've got some questions, as long as it isn't confidential, of course. What type of APFSDS rounds were fired during those test you witnessed? And how much the achived penetration results were better from 'official' ones?

Best regards!!!

Sorry, not in a position to give that kind of detail. The tests were held against varying thickness of a nominal RHA rated armour plate (typically representing known "enemy" platforms, and set at realistic angles to represent front glacis etc...)

All I'm able to say that 650mm RHA equivalent is clearly understating the penetration capability of a Euro 120mm calibre weapon be it rifled or smoothbore.

 

[Aussie Digger]

As to SPG's v tank guns, the guns on modern MBT's are designed to be fired on the move as well as static. SPG's only fire from a braced (ie: supported) static positions, which is one reason they are able to employ such heavy calibre guns. Unfortunately the net result of the heavy duty suspension etc used on SPG's is that they possess significantly lower maneuvrability levels than mbt's. Every design feature is a compromise in some aspect as mentioned by gf...