Arjun Main Battle Tank (MBT)

[Damian]

Noob question. Wouldn't the stabilization be designed in such a way that it supports one design over another? For eg: a 125mm smoothbore gun would work slightly differently as compared to a 120mm rifled gun or a 120mm smoothbore gun when installed on the same platform.

Don't think so, there migh be issue with gun weight, but recently Greeks converted some Leopard 2A4's for training, they are now armed with 105mm rifled guns to use all spare 105mm ammunition for training. This is because 120mm ammunition is to valueable and there is less of it than huge numbers of 105mm + old tanks with 105mm guns will soon be retired.

 

[LurkerBaba]

Okay here is what I understood

A projectile from a smooth-bore gun has only linear momentum. Rifling introduces an extra angular momentum. This extra angular momentum coupled with linear momentum makes a rifled gun more accurate.

However, maintenance costs of rifled guns outweigh these gains in accuracy.

Correct ?

 

[Damian]

But nobody proved, never that rifled gun is more accurate than modern smoothbore gun. As I said, in all tests and competitions smoothbore armed tanks gained more points that rifled armed tanks.

All these stories about long ragne shots are not detailed, we need to remember that crews that gained these shots were commanded by high rank officers, nobody knows how many ammunition they spent until they hit target.

Firing conventional ammunition farther than 4,000m is waste of ammunition, no ordinary crew will ever do that.

So every fact is against rifled gun.

No proof that it is more accurate.
It's ammunition is outdated and/or less capable.
It's service life is shorter.
It's cleaning and maintnance is more difficult.
Production is more complex and expensive + add here cost of more often barrel change compared to smoothbore gun.

 

[methos]

Okay here is what I understood

A projectile from a smooth-bore gun has only linear momentum. Rifling introduces an extra angular momentum. This extra angular momentum coupled with linear momentum makes a rifled gun more accurate.

However, maintenance costs of rifled guns outweigh these gains in accuracy.

Correct ?

This is true for old cannons, rifles and guns, which all do not shoot fin-stabilized ammunition. Fin-stabilization has very good results, the lastest ammo can hit a 1 x 1 m target at 4,000 m range at a very high probability, if the gunner does aim at the center. This is better than all non-fin-stabilized rounds.

 

[p2prada]

Okay here is what I understood

A projectile from a smooth-bore gun has only linear momentum. Rifling introduces an extra angular momentum. This extra angular momentum coupled with linear momentum makes a rifled gun more accurate.

However, maintenance costs of rifled guns outweigh these gains in accuracy.

Correct ?

Higher accuracy claims for rifled gun is just theoretical.

There are no advantages for the Rifled gun. It's only advantage was firing HESH and that's gone.

This is true for old cannons, rifles and guns, which all do not shoot fin-stabilized ammunition. Fin-stabilization has very good results, the lastest ammo can hit a 1 x 1 m target at 4,000 m range at a very high probability, if the gunner does aim at the center. This is better than all non-fin-stabilized rounds.

The last I heard Rosonboronexport gave pk of 60% for T-90 in Saudi Arabia for targets above 4000m.

 

[Damian]

The last I heard Rosonboronexport gave pk of 60% for T-90 in Saudi Arabia for targets above 4000m.

With older FCS and older gun. T-90MS have modern Sosna-U FCS and new gun with MRS system.

 

[p2prada]

With older FCS and older gun. T-90MS have modern Sosna-U FCS and new gun with MRS system.

I think the FCS is Kalina. The Gunner sight is Sosna-U.

 

[Damian]

Yeah You are right, my mistake... You can get get sick with all these names, Irtish, Ramka, Redut, Kalina. ;P

 

[p2prada]

Yeah You are right, my mistake... You can get get sick with all these names, Irtish, Ramka, Redut, Kalina. ;P

Dealing with European names are difficult. Heck give 10 or 20 years and you will see whole new definitions of weapons and other things once India and China become mainstream defence tech powers with all names in Sanskrit and Mandarin.

Lucky for us math is universal.

 

[pmaitra]

Okay here is what I understood

A projectile from a smooth-bore gun has only linear momentum. Rifling introduces an extra angular momentum. This extra angular momentum coupled with linear momentum makes a rifled gun more accurate.

However, maintenance costs of rifled guns outweigh these gains in accuracy.

Correct ?

Higher accuracy claims for rifled gun is just theoretical.

There are no advantages for the Rifled gun. It's only advantage was firing HESH and that's gone.

LB,

Again, one more misleading comment from P2P.

A spinning projectile will have a less parabolic path than a non-spinning one.

This is true:

• in theory.
• in practise.

This is tue:

• for 7.62mm projectile.
• for 120mm projectile.

Methos explained how smoothbore guns compensate for the loss of accuracy, using fins, etc.. If a projectile is shot from a rifled gun and then it is converted to a smoothbore (keeping pressures and mass same), the projectile shot from the smoothbore is guaranteed to lose some of its accuracy. There is no doubt about that.

Now, for that particular instance where a smoothbore gun outperformed a rifled gun, it could be a variety of factors, but as I had said, taking away the spin from a projectile does not improve the accuracy, but reduces it.

Note that they still use rifling in assault rifles, because, it is difficult to mass produce ammunition with fin stabilisers etc., because AR bullets are tiny compared to Tank rounds.

Here is a relevant and reasonable justification, but this can get drowned in a whole lot of information, that may be correct, but totally irrelevant and does not answer the question:

But a smoothbore that does not put a spin on the shell can fire at higher velocities while the pressure is lower. Should I say 25% difference in reduction in friction does the trick. The stabilization system, recoil coupled to a modern FCS managed greater accuracy levels as compared to the CR2s gun.

HESH doesn't come into the picture when talking about accuracy. Technically, a HESH can be fired from both a smoothbore and a rifled gun.

 

[pankaj nema]

The Arjun's rifled gun has been made after APPROVAL of the Army and after YEARS of
extensive research by DRDO scientists on whether Rifled or Smoothbore gun should be made

There is plenty of technical material on the net on this subject

It is mentioned on the internet that India Pak Armoured battles will be close range ones that is the shot will
be fired from just one Kilometre or so

And in such close ranges rifled guns are better for greater accuracy and First shot kill probability

The Armoured school 's motto in the Armoured school at Ahmednagar
where they train Indian Army's Armoured corp soldiers is written as " One shot one kill "

Also it has been mentioned that rifled guns produce more Kinetic energy thereby destroying the target
completely

 

[pmaitra]

The Arjun's rifled gun has been made after APPROVAL of the Army and after YEARS of
extensive research by DRDO scientists on whether Rifled or Smoothbore gun should be made

There is plenty of technical material on the net on this subject

It is mentioned on the internet that India Pak Armoured battles will be close range ones that is the shot will
be fired from just one Kilometre or so

And in such close ranges rifled guns are better for greater accuracy and First shot kill probability

The Armoured school 's motto in the Armoured school at Ahmednagar
where they train Indian Army's Armoured corp soldiers is written as " One shot one kill "

Also it has been mentioned that rifled guns produce more Kinetic energy thereby destroying the target
completely

In close quarter combat, a rifled gun will almost always have an advantage over a smoothbore, because, imagine a smoothbore where they use fins to spins the projectile; in that case, the projectile will have to travel some distance for the fluid (air) to act on the fins and start spinning the projectile. However, by then, the projectile will have already covered much distance and lost accuracy.

Also, Indo-Pak conflicts will be short and intense, so, unlike a long drawn war in case of an envisaged NATO-USSR conflict, life of a barrel and maintenance is not a big concern.

So, rifled gun was chosen for Arjun, and a good decision, from my understanding.

 

[Damian]

More talk from people without any knowledge about tanks, their protection and armament.

If range decrease smoothbore becomes even more accurate, and use better ammunition so in all situations smoothbore is better.

This is some short of national sport in India, to defend stupid decisions?

Many arguments were made to show how idiotic was decision to keep with rifled gun. And like fanatics they still defend this decision.

May I ask one thing, what You will do if ammunition factory will be bombed in case of war? From whom You will buy ammunition? From Mars people?

This is another reason why nobody bothers with rifled gun if smoothbores are better and are wide spread, You can buy ammunition from anyone in case of emergency.

Arjun with current armament and it's ammunition should not be even treated as a tank.

Poor anti tank capabilities despite of fact that it use single piece ammunition that have shorter penetrators than 125mm guns, lack of HEAT ammunition, and focus on outdated HESH... it's more heavy armored self propelled gun in turret, designed for infantry support than being real MBT.

 

[LurkerBaba]

A spinning projectile will have a less parabolic path than a non-spinning one.

This is true:

• in theory.
• in practise.

This is tue:

• for 7.62mm projectile.
• for 120mm projectile.

Agreed, thats Physics 101.

Methos explained how smoothbore guns compensate for the loss of accuracy, using fins, etc.. If a projectile is shot from a rifled gun and then it is converted to a smoothbore (keeping pressures and mass same), the projectile shot from the smoothbore is guaranteed to lose some of its accuracy. There is no doubt about that.

Now, for that particular instance where a smoothbore gun outperformed a rifled gun, it could be a variety of factors, but as I had said, taking away the spin from a projectile does not improve the accuracy, but reduces it.

Fin Stabilization (or drag stabilization ?), takes into account the fact that air is viscous. Fins give extra stability in a fluid, a rotating projectile on the other hand would loose energy quickly. This is probably what methos is trying to convey.

Also it has been mentioned that rifled guns produce more Kinetic energy thereby destroying the target
completely

Yes, because a projectile from a rifled gun has both linear and angular velocity (assuming initial velocity is the same for both smooth bore and rifled)

 

[Damian]

If rifled gun produce more kinetic energy please explain why the best APFSDS ammunition is for smoothbore guns not for rifled guns?

Compare M829A3 with L27A1 CHARM3 or APFSDS round for Indian rifled gun? L27A1 looks at least modern, while that one for Indian gun is a joke for todays standards (world wide).

(M829A3, L27A1, Indian APFSDS for Arjun gun).

Even Indian T-72M1 and T-90 tanks can fire and fire better APFSDS ammunition.

 

[pankaj nema]

@ Damian

Why should nt we trust our own DRDO and Indian Army officials rather than a Polish citizen

DRDO has not made a unilateral decision of Rifled guns Indian army has asked for it

 

[pmaitra]

Agreed, thats Physics 101.



Fin Stabilization (or drag stabilization ?), takes into account the fact that air is viscous. Fins give extra stability in a fluid, a rotating projectile on the other hand would loose energy quickly. This is probably what methos is trying to convey.




Yes, because a projectile from a rifled gun has both linear and angular velocity (assuming initial velocity is the same for both smooth bore and rifled)

Yes, I think that is what he is trying to say.

 

[Damian]

Why should nt we trust our own DRDO and Indian Army officials rather than a Polish citizen

Maybe because Polish citizen knows how idiotic is to belive in everything own goverment or defence agencies tell You? Maybe because Polish citizen know that if bunch of fanatics start to prize own industry without any constructive criticism then this industry will sold Army outdated or failed products?

We had same situation as India with Pronit ammunition, everyone was happy, we have superammunition and hey, in the end 50% of rounds were poor quality, it was mainly fault of Israeli company manufacturing penetrators but welcome in reality. If You not make constructive criticsm, then say hello to poorly equiped army with many problems.

DRDO has not made a unilateral decision of Rifled guns Indian army has asked for it

Then officers that done that are idiots. India without any problems could order 120mm smoothbore guns from Germany, and nobody would complain because India is seen in Europe as Democratic country where minorities are not in danger and all that crap. Israel also could sell their 120mm smoothbores to India.

As I said, there is no problem with rearming Arjun with a smoothbore, but it seems that somone in India have interest to see first Indian MBT with outdated gun and ammunition.

But nooo, nobody ask question, new toy is here and nobody is even interested to make proper analize of it, constructive cirticism and later upgrade vehicle.

This is how vehicles are done in countries where arms industry is well developed, when vehicles enters production work on upgrading it is performed from a long time allready.

This is what makes people like You silly, they got new toy and are happy, and even more silly and idiotic is when they start to onanize looking on that new toy in the same time criticizing every possible adversary to the level when they call it primitive, etc. This what most of You do saying about Pakistan or PRC, but such arrogance will end with unnececary casualties and shock if war brake out.

 

[pmaitra]

This is some short of national sport in India, to defend stupid decisions?

Is it a national sport in Poland to have a degree in Fine Arts and then pretend to be an expert in tanks?

Many arguments were made to show how idiotic was decision to keep with rifled gun. And like fanatics they still defend this decision.

Go to the university and take a course on fluid mechanics instead of blurting out nonsense.

This is another reason why nobody bothers with rifled gun if smoothbores are better and are wide spread, You can buy ammunition from anyone in case of emergency.

If you cannot offer an explanation, why should anyone believe you? Do you think your audience is a bunch of parrots?

Arjun with current armament and it's ammunition should not be even treated as a tank.

As you wish, ma'am.

Unfortunately, you'll have to do better than that to convince people.

 

[Damian]

Is it a national sport in Poland to have a degree in Fine Arts and then pretend to be an expert in tanks?

I at least read books about them and listen people better informed than You.

Go to the university and take a course on fluid mechanics instead of blurting out nonsense.

Yeah, designers all over the world are idiots, they choose smoothbore over rifled guns, when rifled are so special, so magic. Go and tell designers in Rhinemetall that they are idiots, go, do not shy!

If you cannot offer an explanation, why should anyone believe you? Do you think your audience is a bunch of parrots?

Mommy teached You how to read with understanding?

As you wish, ma'am.

Unfortunately, you'll have to do better than that to convince people.

I convience normal thinking people, not pseudo patriot and fanatic like You.