Tank Guns and Ammunition

[Damian]

re: Tank Guns: Photo & Dicussion thread..

Interesting is that You are not providing any sources, but in the same time, You want everyone to belive You.

 

[Akim]

re: Tank Guns: Photo & Dicussion thread..

More arguments:

Factor defining power of gun, square of the caliber. Under the same conditions (lenght, etc), but differing in caliber, 125mm gun will be about 10% more powerfull than 120mm.

So even if you have 125mm gun with 5.3m lenght and max pressure of 6.500 bar, it is equivalent to 120mm with 7100 bar and 5.3m.

It further confirms that 125mm gun with 6m (additional lenght) is significantly more powerfull than RH L/44, approaching L/55.

Not so. It is ordinary physics. To give speed to the shell of greater caliber at less starting distance, vice versa it is necessary to increase pressure. This means thickening of the trunk. New charge chamber, because "soviet" shot not unitary. Et cetera. I already it is said that the German guns better on technical characteristics, but on battle characteristics they are at one level. If to compare the cannons of "soviet" type to western in one caliber - that in an example Kharkiv КBМ2. Baseline characteristics as at 2А46, and shoots the shells of NATO, but соответсвенно is long anymore in the calibers of L50,although metrical - 6 meters.

 

[militarysta]

Methos -it may be ussefull for You - there is MPa and perforation values -whole pdf in english:
Polish 125mm munitions:
http://www.bumar.com/dywizje_flash/admin/store/images/image-1317723858-link.pdf


and from other factory:
http://www.bumar.com/dywizje_flash/admin/store/images/image-1317723969-link.pdf

 

[hest]

On future Russian IFV (BMP Kurganets) it is also planned as main armament automatic cannon with 57mm caliber:

Here on modernised light tank:

Module:

 

[militarysta]

@Methos
@Damian

And I have confirm thanks to Василий Фофанов from otvga2000

Активная часть С-2 имеет длину 724...729 мм (разброс с учетом допусков). Какой длины сам сердечник сказать не могу поскольку не знаю конструкции носовой части под обтекателем. Порядка 70 см.

So we have very very interesting situation in modern 125mm APFSDS and 120mm APFSDS.

Newest 3БМ60 «Свинец-2»125mm APFSDS have total projecile lenght limitetd to 740mm, they penetrator (balistic cap + rod + fins) is 724...729 мм lenght and only rod is ~ >700mm long. Muzzel vel. is about 1750m/s; speed decrease during the flight is about 60m/s on 1000m range, 2A46M-5 have 600MPa pressure. sabot+rod on velocity have 10,5-11MJ

DM53/63 have whole penetrator lenght "only" 740mm (whit balistic cap, without fins), Muzzel vel. is 1750m/s peed decrease during the flight is about 50-55m/s on 1000m range. Lh-55 R120 have more then 700MPa pressure (L-44 have 670MPa and 1670m/s).
sabot+rod on velocity have 11,5MJ for L-44 and about 11,6MJ for DM43 from L-55 and 15,3MJ for DM53 from L-55 (some sourcs give 12,7MJ) ...

M829A3 have penetrator about 800mm lenght. 1675 muzzel vel. and peed decrease during the flight is about 59m/s on 1000m range. Pressure will be about 700MPa as I remember. Most important - sabot+rod on velocity have 12,1MJ

Without the longest M829A3 the bigger difrences should be in used propelng charge and...sabot construction. Propably teh most important is sabot -due to transfer MJ only to penetrator during fly not for whole SABOT. So in fact this all 11/12-13MJ is not for penetrator during fly.

How big can be difrennce between perforation value shown polish 125mm APFSDS ammo:

Penetrator weight is the same 3,7kg during fly, for NEW modernisation whit composite SABOT muzzel vel is bigger 1650/1724m/s, MPa pressure is LOWER 532/408MPa and new composite SABOT weight only 1,88kg (old -3,85kg).
And what we have? Perforation is better for more then 110mm RHA on 2000m -only for using better and lighter SABOT...

Any ideas?

 

[Damian]

Americans replaced alluminium sabots with composite sabots, I think it was in M829A2 when they for the first time used composite sabots.

 

[hest]

The more calculations you make, you are farer from reality.

3БМ60 «Свинец-2»[/b]125mm APFSDS have total projecile lenght limitetd to 740mm, they penetrator (balistic cap + rod + fins) is 724...729 мм lenght and only rod is ~ >700mm long. Muzzel vel. is about 1750m/s; speed decrease during the flight is about 60m/s on 1000m range, 2A46M-5 have 600MPa pressure. sabot+rod on velocity have 10,5-11MJ

Total projectile is not limited to 740mm, (This is specific figure of Svinets). Indeed, DM-53 can fit in modernised T-72 autoloader.

And you are using figures for older 2A46-M gun, it is not correct...

DM53/63 have whole penetrator lenght "only" 740mm (whit balistic cap, without fins), Muzzel vel. is 1750m/s peed decrease during the flight is about 50-55m/s on 1000m range. Lh-55 R120 have more then 700MPa pressure (L-44 have 670MPa and 1670m/s).
sabot+rod on velocity have 11,5MJ for L-44 and about 11,6MJ for DM43 from L-55 and 15,3MJ for DM53 from L-55 (some sourcs give 12,7MJ) ...

M829A3 have penetrator about 800mm lenght. 1675 muzzel vel. and peed decrease during the flight is about 59m/s on 1000m range. Pressure will be about 700MPa as I remember. Most important - sabot+rod on velocity have 12,1MJ

Care to explain how you "magically" arrive to those figures ?

And there is another question. If DM-53 round is interoperable with RH-L/44 and RH-L/55 guns, being the same, how can it operate under higher pressure on the latter, using the same propellant ?? If it is indeed unified only difference should lie in increased barrel lenght (being the camber, etc unified, the same).

 

[militarysta]

Total projectile is not limited to 740mm, (This is specific figure of Svinets).

Total catrige (projectile) lenght is limiteted to L= 740mm. Due to Korzina-A autoloader. And due to Chlopotov blog, and otvaga.2000.ru.
Of course propelant charge is additional here.

indeed, DM-53 can fit in modernised T-72 autoloader.

Indeed it's BULLSHIT, because there is NO WAY to put in carossele autoloader about 1000mm catrige!

And you are using figures for older 2A46-M gun, it is not correct...

Those figures are taken from otvaga and btvt, and vadimvswar page. So I have no bloody idea how they are incorrect.

And there is another question. If DM-53 round is interoperable with RH-L/44 and RH-L/55 guns, being the same, how can it operate under higher pressure on the latter, using the same propellant ?? If it is indeed unified only difference should lie in increased barrel lenght (being the camber, etc unified, the same).

It's not. Using DM-53 is forbiden for L-44 due to max pressure reson. For L-44 proper one is only DM63. It's longer story.
In some case it's possible to fire DM53 from L-44 due to hige construction pressure limit in L-44 (more then 710MPa) but only for well-defined air temperature and catriges temperature. Due to sefty reson and barrel liftime it's forbiden now.

Care to explain how you "magically" arrive to those figures ?

From sources -it's simple -I have many many sources full of datas.

 

[militarysta]

T Indeed, DM-53 can fit in modernised T-72 autoloader.

.

Indeed it's BULLSHIT, because there is NO WAY to put in carossele autoloader about 1000mm catrige!


'How to hell you want to put >1000mm lenght catrige in "in modernised T-72 autoloader." when it's longer then half thick of hull?
It's impossible in carussel style autoloader, and it's reson why in T-72/T-90A family penetrator lenght never will be so long like in M829A3 or others western APFSDS. Deal with it.

In DM53 and 3БМ60 «Свинец-2» it's comparable whole penetrator lengt (balistic cap, rod, fins):

3БМ60 «Свинец-2» - 724-729mm
DM53 - 740-760mm

 

[Akim]

The more calculations you make, you are farer from reality.


Total projectile is not limited to 740mm, (This is specific figure of Svinets). Indeed, DM-53 can fit in modernised T-72 autoloader. .

-
Apparently in Kharkov all these "stupid" that did they have to work out a feed AL(autoloader.) in T-72-120, but not took the modernized Tagil "Acorn"(Желудь) ? At turrent AL am the limitations, but descriptions of shells with the separate-case loading, do not yield a unitary projectiles NATO. A question is in other. When we see them in the army?

 

[hest]

Total catrige (projectile) lenght is limiteted to L= 740mm. Due to Korzina-A autoloader. And due to Chlopotov blog, and otvaga.2000.ru.
Of course propelant charge is additional here.

Statement is "modernisation of autoloader and adoption of new gun to fire new rounds (Svinets) of penetrator of increased lenght 740mm"

It does not mean it is the maximum length allowed (by dimensions). It is same situation as with old autoloader, it could use projectiles longer than Mango (penetrator lenght up to about 680mm), contrary to many's beliefs.

Indeed it's BULLSHIT, because there is NO WAY to put in carossele autoloader about 1000mm catrige!

I am not going to argue about how it is done (I do not know), howewer it is official statement of producer site.

Those figures are taken from otvaga and btvt, and vadimvswar page. So I have no bloody idea how they are incorrect.

So you now use btvt for your purpose ?? Funny thing is, you are now hypocritical. You got your figures from here, howewer it is not accurate and based on old information. And why don't you look at all the "figures" ?? 2A46M5, 6000 bar... M256 (RH L/44), 62000 bar maximum chamber pressure

In Ukrainian analogue KBA-3 max pressure is 6500 bar, 2A46-M5 should be in that order if not more.

Fact is that new gun 2A46-M5 was adopted to use new rounds Svinets which as stated by producer, use more energic propellant. Mango was close to limit of older gun already with 5660 bar in chamber (6000 bar), Svinets would just surpass limit of older gun therefore it requires adoption of new model.

It's not. Using DM-53 is forbiden for L-44 due to max pressure reson. For L-44 proper one is only DM63. It's longer story.
In some case it's possible to fire DM53 from L-44 due to hige construction pressure limit in L-44 (more then 710MPa) but only for well-defined air temperature and catriges temperature. Due to sefty reson and barrel liftime it's forbiden now.

I understood, that only difference was use of propellant of better quality which was not so sensible to temperature variations (DM-53A1 and DM-63). Howewer it is not increase in resultant pressure.

So you say, that older sensible propellant on DM-53 under specific conditions (but not on practical average) increase in pressure can be employed by L/55. But this is not an incentive as you want it to be.

So on average, rounds fired from L/44 and L/55 will not reach 7000 bar.

From sources -it's simple -I have many many sources full of datas.

I howewer doubt your correct interpretation of provided figures.

About DM-53 I had figures:

From L/44 11.6 MJ
From L/55 12.7 MJ

How do you transform such provided data on things as 15 MJ is what makes me doubt about your "calculations"

 

[Damian]

Statement is "modernisation of autoloader and adoption of new gun to fire new rounds (Svinets) of penetrator of increased lenght 740mm"

It does not mean it is the maximum length allowed (by dimensions). It is same situation as with old autoloader, it could use projectiles longer than Mango (penetrator lenght up to about 680mm), contrary to many's beliefs.

I am not going to argue about how it is done (I do not know), howewer it is official statement of producer site.

It is immposible to place in this type of autoloader, APFSDS projectile longer than ~740mm (full assembly), physical dimensions not allow to do that.

 

[militarysta]

Statement is "modernisation of autoloader and adoption of new gun to fire new rounds (Svinets) of penetrator of increased lenght 740mm"

It does not mean it is the maximum length allowed (by dimensions). It is same situation as with old autoloader, it could use projectiles longer than Mango (penetrator lenght up to about 680mm), contrary to many's beliefs.


I am not going to argue about how it is done (I do not know), howewer it is official statement of producer site.

Physical dimensions DM53/63 not allow to do that with caruselle autoloader. It's impossible to "put in" 1000mm long catrige when it's longer then hall thickness of the T-72 family hull. And this "statement of producer site" is about using round in gun not in autoloader...

So you now use btvt for your purpose ?? Funny thing is, you are now hypocritical. You got your figures from here, howewer it is not accurate and based on old information. And why don't you look at all the "figures" ?? 2A46M5, 6000 bar... M256 (RH L/44), 62000 bar maximum chamber pressure

Becouse for L-44 I have military manuals where proper values are fixed. And never is placed infos about bigger then ~600MPa chamber pressure for new 2A46M5. And ukrainian KBA-3 can be just slighty better.

So on average, rounds fired from L/44 and L/55 will not reach 7000 bar.

From L-44 definetly not.
for L-44 Muzzle V for L-44 is between 1640 and 1660m/s and MPa pressure between 500 and 560MPa.

In fact MPa is not relevant factor during perforation -the same as muzzle velocity.
Optimum velocity for WHa rods is between 1700-1800m/s, for DU rod its 1500-1600m/s.

 

[hest]

Physical dimensions DM53/63 not allow to do that with caruselle autoloader. It's impossible to "put in" 1000mm long catrige when it's longer then hall thickness of the T-72 family hull. And this "statement of producer site" is about using round in gun not in autoloader...

It is specifically stated: 120mm gun M-393 for modernisation of T-62, and M-395 for modernisation of T-72.

And Russian upgrade does not offer additional bustle loading mechanism.

Becouse for L-44 I have military manuals where proper values are fixed. And never is placed infos about bigger then ~600MPa chamber pressure for new 2A46M5. And ukrainian KBA-3 can be just slighty better.

Svinets uses more energic propellant and it cannot be fired from older gun, only on newest 2A46M5.

For Ukrainian analogue of modern production figure of 6500 bar is given and it is not any better.

From L-44 definetly not.
for L-44 Muzzle V for L-44 is between 1640 and 1660m/s and MPa pressure between 500 and 560MPa.

What is pressure created by propellant of DM-53 (at normal, average conditions) and DM-63 rounds ?

In fact MPa is not relevant factor during perforation -the same as muzzle velocity.
Optimum velocity for WHa rods is between 1700-1800m/s, for DU rod its 1500-1600m/s.

Increase of pressure and bore lenght (thus increase of energy) is very important factor. On those factors improvement is driven on achievement of superior penetration and effective range of modern rounds, and also of perspective, as gun 2A82.

 

[hest]

It is immposible to place in this type of autoloader, APFSDS projectile longer than ~740mm (full assembly), physical dimensions not allow to do that.

Svinets does not necessarily represent maximum dimensions allowed (740mm), that is what I corrected. What is exact limitation, as 680mm for old autoloader, is not certain.

 

[Damian]

It is specifically stated: 120mm gun M-393 for modernisation of T-62, and M-395 for modernisation of T-72.

And Russian upgrade does not offer additional bustle loading mechanism.

It is immposible to use in T-72 tanks autoloader, NATO standard ammunition, period.

What they can do is just develop new two piece ammunition and try to put there penetrator used in some version of NATO standard ammunition.

Is this is possible, in theory yes, in reality it might be difficult.

 

[militarysta]

It is specifically stated: 120mm gun M-393 for modernisation of T-62, and M-395 for modernisation of T-72.

And Russian upgrade does not offer additional bustle loading mechanism.

Ok, but it's doesn't change fact that it's impossible to put 1000mm long catrige in carosuell autoloader when is impossible to place longer then L=750mm projectile. Sekond fact is that 1000mm long smth. is more then half thick of T-72/90 hull so is no option to place so ong projectile in Korzina style autoloader.
Due this two facts (no my opinnion but fact...) there are two options:
a) there is mistake on this page (rather not)
b) it was only about gun and possible to use ammmo but not autoloader.

Svinets uses more energic propellant and it cannot be fired from older gun, only on newest 2A46M5.

Older gun had about 500-600MPa.

For Ukrainian analogue of modern production figure of 6500 bar is given and it is not any better.

It's not better becouse?

What is pressure created by propellant of DM-53 (at normal, average conditions) and DM-63 rounds ?

For Dm-53 it's depend on temperature - for 10degree its 550MPa and 1650m/s, for 25 degree its 600MPa and 1705m/s, and for more then 30 its up to 650MPa and even 1750m/s.
DM-63 it's not so depend on temperature - constans is 550MPa and 1660m/s.
As I remember those data where for L-44.

Increase of pressure and bore lenght (thus increase of energy) is very important factor. On those factors improvement is driven on achievement of superior penetration and effective range of modern rounds

No it's not. Whole idea is to transfer more MJ for penetrator only.



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Swedish pilprojektil 95 based on M338 IMI:

 

[militarysta]

For older mesurments it was:

blue - 1005mm
red - 800mm
green - 940mm

 

[militarysta]

Better draw, with both values for old and new mesurment. IMHO rather lower values, but due to photos mesurment error this 800mm for rod could be.

 

[Akim]

For older mesurments it was:

blue - 1005mm
red - 800mm
green - 940mm

You will look at ML of Т64-(80). No limitations in the use penetrator is long it is not. And in Russia plenty of all modifications of Т- 80, except for Т-80UD.