120mm vs 125mm (more on guns)

[M1A1HA]

The major NATO MBTs, such as the new Abrams, Ariete, challenger 2, Leclerc, new Leopard, Mekava, all use 120mm main gun, while all former Soviet MBTs use 125mm main gun. Is there a reason for the 120mm caliberation being so puplar among the westen allys? How about the Soviet 125mm?

[Walt]

The 120mm gun was developed by the Germans when they figured out the 105mm wouldn't be up to spec killing T72s and whatever would come later. When other countries started to develope their own MBTs they latched on to the gun. NATO designated it as a standard, much like the NATO 7.62mm, and 5.56mm rounds. There's all kinds of NATO standard ammo, 20mm, 105mm, 155mm, 127mm, 40mm, 30mm, bla, bla, bla...

As for the Russin 125mm, I have no idea. They have some wierd standards, the 37mm and 7.62x39 for example. I know the 152mm guns are the correct measurement for 6" guns (155mm=6.1" not 6"). I would assume they were designing all their new guns to fire old ammo. The russians are anal about that sort of thing, They're still storing allot of their old junk. I don't know if 125mm is a little smaller than 5", so I don't know where they got that.

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[Dar]

This may not be applicable to the 155mm, but one thing the Russians/Soviets do is assign a different diameter to a weapon and ammo if it conflicts with a pre-existing weapon and ammo. I can't think of any real examples right now (I'm at work--no access to my library!), but if they had a 120mm gun, mortar, and rocket, they would actually call them, for example, the 120mm gun, the 122mm mortar, and the 124mm rocket. In this way, a commander doesn't have to worry about specifying what type of ammo he needs. He just states "122mm" and he know he'll get mortar rounds--even though they're actually 120mm.

Dar

[Guest Germanboy]

I have also read somewhere that the Russians loved the idea to fire undercalibrated ammo looted from the ammo dumps of 'Blueland'. I think you could do that with the AK47 and with the 82mm mortar. Could be off on the info, it is a while that I read it, we still had the cold war then. And I have no clue whether you actually could do that with the 125mm MBT guns. They might also just like the overkill.

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Andreas

[Sergeant Huang]

Hi, Guys :

Here are some real stories in the desert

storm about 120 mm gun of M1A1 and 125 mm gun

of T-72. I don't have the book in hand, it comes from my memory, oh, it is from a book

written by Tom Clancy.

1. A M1A1 was stuck in mud, while waiting for

M-88 (recovery tank), some T-72 showed up,

M1A1 killed them (3 or 4 in total ??) except one left, M1A1 got hit from the last T-72, in the distance of 400-500 meter, the 125 mm gun of T-72 only made a small concave

of 2 inches on the turret. The last T-72 fell

back to a sand hill before M1A1 can shoot back. But, the 120 mm shell from M1A1 went

through the sand hill and killed the poor

T-72.

2. One shot Two kills :

A M1A1 fired one shot at a T-72, not only

killed this T-72, but also one T-72 right

behind it.

So, am I making 120 mm gun and 125 mm gun

clear ??

Sgt.H

[Trooper]

No, you're making ammunition and armor quality clear. It's more than just the gun. The same 125mm cannon on the same T-72 that got killed after bouncing off the same Abrams might well be capable of firing a more modern piece of ammunition which under the same circumstances could slice through that Abram's armor.

There is also perhaps something to be said for the mission philosophy as well.. Given that one of the primary roles of Russian tanks seems to be anti-infantry or anti-defense work, and the vastly larger proportion of HE rounds carried compared to a Western tank, maybe it does well to consider that the explosive content of the round is proportional to the square of the radius of the round. You basically get a bigger bang out of the 125mm.

As an aside to Walt's post, NATO's first 120mm gun was the British rifle originally fielded in the 1950s in Conqueror, then Chieftan, then Challenger. This is some 20 years before the Germans put their 120mm into production in Leopard 2, so the Brits must have been well on the ball there! There is no commonality between rounds for the L11/L30 British 120mm rifles and the 120mm smoothbores.