Difference between the smoothbore and rifeled barrels of the main gun of a tank

[Deepinder Kundr]

I've been searching from so long that why these days most of the armies are upgrading their tanks with smoothbore main guns instead of rifeled one but im unable to find the correct ans so plzz can anybody tell me that what is the advantage of smoothbore guns over rifeled one's
and why they have been accepted widely

 

[Waylander]

Modern subcaliber KE rounds (APFSDS-T) require a non rotating flight as they are stabilized by fins. So for this kind of round one doesn't need a rifled barrel for accuracy. The KEs fired out of the British L30 are specially designed not to rotate even while fired out of a rifled gun.

As modern fire control systems coupled with modern non KE ammo (like HE) achieve high accuracy without the rifling there is no real case for using a rifled gun in these days and age.

The Brits really like their HESH round which performs much better when fired out of a rifled gun but I fail to see the big advantages of it compared to a modern programmable HE round.

I will never understand why the Indians went with a rifled gun for the Arjun. They would have access to a much bigger selection of modern ammunition with 120 or 125mm smoothbores. Now they have to design all the ammo by themselves.

 

[vivtho]

I've been searching from so long that why these days most of the armies are upgrading their tanks with smoothbore main guns instead of rifeled one but im unable to find the correct ans so plzz can anybody tell me that what is the advantage of smoothbore guns over rifeled one's
and why they have been accepted widely

If you plan to only fire shells from your gun then rifled main guns are always better in terms of accuracy and range. Also IIRC rifling degrades the effectiveness of HEAT shells compared to smoothbores. Smoothbore guns have the advantage that they are not limited to using only cannon shells but can also fire guided missiles from the gun tube.

There's at least one program which is trying (I don't know if they've succeeded yet) to develop a missile that can be fired from a rifled gun. The missile is launched encased in a sabot which is allowed to rotate independently of the missile. I guess this is only possible with non-wireguided missiles though.

 

[Waylander]

The Israeli Lahat missile is integrated into 105mm rifled guns as well as the Indian 120mm rifled gun.
So this missile can be fired from rifled and smoothbore guns.

HEAT becomes less and less important even on smoothbore guns. Carrying HEs with delayed fuze capability should be good enough for everything up to an IFV with KEs being used against MBTs.

120mm smoothbores just offer a much more diverse range of ammunition. You don't find stuff like porgrammable HEs, canister, PELE or MPAT for the British and Indian rifled guns.

 

[vijayender]

A smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.

A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity.

 

[Waylander]

You know that you gave an answer to a question nobody asked?

Back to topic.
One could add that the proliferation of the Abrams and Leopard II led to 120mm smoothbores getting somewhat of a drive. Many countries using the same gun keeps it alive. The same applies to all the eastern smoothbore T tanks.
Big players tend to make a trend.

 

[vivtho]

Somewhat OT...
Do smoothbore guns have to be relined as frequently as rifled ones?

 

[winnyfield]

You know that you gave an answer to a question nobody asked?

Back to topic.
One could add that the proliferation of the Abrams and Leopard II led to 120mm smoothbores getting somewhat of a drive. Many countries using the same gun keeps it alive. The same applies to all the eastern smoothbore T tanks.
Big players tend to make a trend.

The British have been looking to introduce smoothbore cannons (I think its been cancelled) because of the lack of ammo development for rifled guns. Everyone else is using smoothbores with steady research into new ammo being done by US, German and Israeli companies.

Somewhat OT...
Do smoothbore guns have to be relined as frequently as rifled ones?

I guess not. Smoothbores have less barrel wear

 

[Waylander]

I know some years ago I've posted a picture of a L/55 fitted to a Challi 2. Can't find it anymore though.

Not that the British L30 with DU-KE and HESH is not ok for todays conflicts but as you say they are on their own when it comes to ammo development.
Not even the British and Indian 120mm guns are compatible...

 

[Deepinder Kundr]

okey finally i got what i've been looking for thanks to all of you especially mr waylander

 

[TrangleC]

One thing I'd like to add because it is something I didn't understand for a long time myself and maybe you are in the same position.
I knew that KE/sabot rounds were fin stabilized and thus work better when not rotating, but for a long time I didn't understand why they are fin stabilized.

The reason is that the longer and thinner a projectile is, the faster it has to rotate to be stabilized. I forgot the name of that physical principle. Of course KE sabots have to be long and thin to be good penetrators, too long and too thin to still be stabilized by rifling.