"120mm mortars - *all* smoothbore ammo compatible?!?" Topic

So I was doing some wikidiving just a second ago, and came across the Russian 2B11 120mm mortar, which is apparently a different baseplate fitted to the WW2-era 120mm tubes.

The Germans like the Russian 120mm PM-38 so much they built their own copies during WW2.

But it seriously looks like all the 120mm smoothbore mortars, no matter what company made the tube, can fire any 120mm fin-stabilized ammo regardless of maker!

Is that really correct?!? Probably the only time in history that both NATO and WARPAC weapons could fire each other's ammunition straight out of the crate!

I honestly don't know, but I'd sure hate to be the mortar crew testing this "hypothesis". I've watched enough vids from the MidEast of rounds going off inside the tube, even on 60mm mortars it's a mess.

That wouldn't surprise me, since they are the same diameter, afterall.

And, if they're copies of others, then they'll be very similar in design, so…..

One minor problem. When Stalin was to have a 150mm gun displayed to him they shipped 150mm rocket ammunition. Instead of sending the men who made the error to the gulag he insisted that the rounds should be identified as a different caliber so a 150mm shell might be identified as 152mm if another incompatible round was identified as 150mm.

British 3" mortars for example were not 3" calibre, they were 81.2mm iirc, so were capable of firing German ammo

I just read a book where a Fallschirmjaeger is quoted as saying they had both German & Soviet mortars (8.0 & 8.2 cm)in Holland. They liked the Sov mortar but hated its unreliable captured ammo so they used Ger ammo in the Sov mortar.

Regarding my young day experience I can state that the NATO 81mm rounds fire into the soviet/chinese 82mm tube, but not the contrary.
Hope it helps.
Cheers.

Tirailleur corse, I'm pretty sure the Soviets designed the 82mm mortar for just that reason: it could fire German 81mm rounds, but not the reverse. Which illustrates pretty well that mortar ammo is pretty much interchangeable. As noble713 notes, I'd hate to be that first guy to try out new ammo.

Coming out the tube is not the same as landing where you want it. ewven a very small difference allow a loss of muzzle velocity that drops range a good deal.Unless you have a complete set of fire control equipment with the new tube yu are not likely to hit anything.

owen

Even if it fits, this does not mean, that a crew can fire the ammo in a reliable way due to a different firing table etc to each ammo type and sort

You can overcome these problems if you are self observing and "close enough is good enough".

Unless the ammo you are using has a lot heavier charge than the tube that is taking it. And the more blowby there is around a projo the very much faster you are going to erodse that tube.

Even if the tube doesnt turn into secondary missles, it will be no fun when your 120mm round blops out 10 yards and goes off. As said above, let the infantry try that stuff foirst, nothing I want to be around.

owen

supporting Owen
If the gas ring of the mortar round is not even closing off enough, the round will be a short round or worse not leaving the tube.

Even self observing with unknown rounds and no firing table is just a gamble; each mills or degree difference in direction or elevation or even changes in charge elements lets the round jump around without getting close.

wargame rules do not always meet the real world and many take them for real…..

What I was thinking was that having a 120mm mortar would let you buy ammo from pretty much anyone, because you would have firing tables for the ammo from your suppliers.

I've noticed that the Russians have been pushing guided HE-frag artillery rounds as opposed to anti-tank rounds, particularly laser-guided.

If it was that simple…

Lion it is not that simple because each shell/tube combo is just a bit different. Not only do lengths vary, but the amount of expansion the tube does effects Where the round lands. Most everybody understands that the round goes out and the tube recoils, but dont think about it expamnding as well.

Firing tables are worked out initialy with mathmatics, but then they take the guns out ot a range and see what they will really do.

Owen

So you would need to either have the ammo-maker put a few rounds through whatever tube(s) you use to develop the range tables, or do the work in-house?

More or less. Normal fireing tables are established from thousands of rounds. Dont se you getting that many when you are shopping around. Now somethings are standard, like in NATO standard. In which case all should be compatible. it is when you mix and match with others. And remember just because it is called 120mm doesnt mean that is what it really is.

Owen

Just because mortars are the same bore does not necessarily mean the same ammo can be used. eg British 3" (81mm) mortars had a different firing method to everyone else's.
From link
"81 mm Krh/39

(81 mm mortar model 1939)

These were British mortars. Finnish Army had only small of them (ten listed in inventory document from late 1940 calling them 76 Krh/39), which Great Britain presumably donated or sell to Finland during Winter War. Finnish military never issued them to frontline troops. This was likely due to small numbers, too many differences when compared to other 81-mm mortars and ammunition non-compatibility. Unlike other mortars these didn't have a hammer in their percussion plate, instead they had hammer in tail of their mortar shells. Due to this ammunition of other 81-mm mortars could not be used in these mortars and British mortar shells delivered with these mortars could not be used in other mortars. While other 81-mm mortars had lateral alignment marked as mils these mortars had them marked as degrees. Elevation settings were marked as yards for two British-used mortar shell types. Barred length (measured from percussion plate to rounding in muzzle) was 114.2-cm."