Looking for Firing Tables for tank ammunitions

[FatOtaku]

I'm interested in having a look at firing tables for tank ammunitions, especially the ones during the cold war. But they are hard to come by online. I will be very grateful if anyone can share some. 🙏

[Peasant]

It would be helpful if you narrowed down your request. Cold War era is quite a broad time period. There were dozens of MBTs alone used in that period, sometimes upgraded with a different gun during their lifetime, each gun firing several types of projectiles. 

[FatOtaku]

6 minutes ago, Peasant said:

It would be helpful if you narrowed down your request. Cold War era is quite a broad time period. There were dozens of MBTs alone used in that period, sometimes upgraded with a different gun during their lifetime, each gun firing several types of projectiles. 

I'm interested mainly in US 90mm, 105mm and 120mm tank ammunition. But firing tables for other ammunitions will be interesting to me as well

[old_goat]

I also need some firing tables, for gaming (Arma modding) purposes:

115mm 2A20/U5TS: Im interested in all kinds of ammo, but especially 3BK4 HEAT and OF11 HE-Frag.

100mm D10: 3BK17 HEAT

 

[FatOtaku]

15 hours ago, old_goat said:

I also need some firing tables, for gaming (Arma modding) purposes:

115mm 2A20/U5TS: Im interested in all kinds of ammo, but especially 3BK4 HEAT and OF11 HE-Frag.

100mm D10: 3BK17 HEAT

 

Wow, I appreciate modders trying to get these details right! What is the mod you're working on and what are the mods you've already published? I wanna subscribe to them

[old_goat]

5 hours ago, FatOtaku said:

Wow, I appreciate modders trying to get these details right! What is the mod you're working on and what are the mods you've already published? I wanna subscribe to them

Sorry, private mod for own use. Will not be published. Besides, almost nobody plays Arma2 anymore. 

[FatOtaku]

2 hours ago, old_goat said:

Sorry, private mod for own use. Will not be published. Besides, almost nobody plays Arma2 anymore. 

All good👌

[Stefan Kotsch]

The FT for the 115 mm tank gun have not yet been published anywhere. Even in Russia or Ukraine, this FT has never been uploaded.

[old_goat]

23 minutes ago, Stefan Kotsch said:

The FT for the 115 mm tank gun have not yet been published anywhere. Even in Russia or Ukraine, this FT has never been uploaded.

I find it quite strange... If some of the 125mm firing tables are not secret, why the 115mm is still shrouded in mystery? Even more, there is not even a single photo of the sight picture of the TSh2B-41. All we had is the recently uploaded (but sadly now deleted) video of the later TShSM sight. However, that was enough for me to create a roughly realistic firing table for APFSDS, comparing its to PKT scale. Unfortunately, for HE-Frag and HEAT scale this was only possible only out to 1000-1200 meters.

[Stefan Kotsch]

Yes, that is actually very strange.

[FatOtaku]

15 hours ago, old_goat said:

I find it quite strange... If some of the 125mm firing tables are not secret, why the 115mm is still shrouded in mystery? Even more, there is not even a single photo of the sight picture of the TSh2B-41. All we had is the recently uploaded (but sadly now deleted) video of the later TShSM sight. However, that was enough for me to create a roughly realistic firing table for APFSDS, comparing its to PKT scale. Unfortunately, for HE-Frag and HEAT scale this was only possible only out to 1000-1200 meters.

Not sure if this is something you've already seenTSh2B-41

Edited June 3 by FatOtaku

[old_goat]

2 hours ago, FatOtaku said:

Not sure if this is something you've already seen

Well known drawings, but unfortunately completely useless if somebody wants to know the ballistics of each shell type. These are only for illustrating how the sight picture looks generally. For creating (very) basic firing tables, you absolutely need good quality photos of the real thing. (+ of course some data, like muzzle velocity)

Edited June 3 by old_goat

[old_goat]

I need the opinion of more knowledgeable people here.

Im trying to create a realistic firing table for the 115mm gun for a game (Arma). Sadly, the amount of data available is very limited, and the results are quite confusing. The game is using a rather primitive method for ballistics, using only two values: muzzle velocity and air resistance. Despite this, its quite acceptable. With the help of real firing tables, I was able to create quite realistic ingame ballistics for the 100mm D10 gun. Most values in the game's calculator program match with real world data, with all kinds of ammo. But with the 115mm gun, I ran into quite serious problems, especially with 3BK4 HEAT, numbers just do not match at all. I'll give an example below.

Data for 100mm D10, 3BK5:

muzzle velocity 900m/s

direct shot range for 2m high target: 960m

direct shot range for 2.7m high target: 1100m

All of these are almost spot on in the game. Gun elevation values do not match precisely, but still very close to real world values, out to 3000m.

Data for 115mm 2A20, 3BK4:

muzzle velocity 950m/s

direct shot range for 2m high target: 990m

direct shot range for 2.7m high target: 1200m

Things get out of control here. If I set up the air resistance of the shell to match the 2m/990m direct shot, then the 2.7m/1200 will not match at all. If I zero the range to 1200, the trajectory height will be around 3.3 meters, waaaay too high. Its simply impossible to tweak air resistance value to match both 2m and 2.7m targets. I didnt experience this phenomenon with 100mm APBC,HE,HEAT and APDS. 

To add further confusion, then there is the only known image of a T-62 gunsight that shows the ballistic scale. Im using the MG scale for esitmation. For the D10 gun, HEAT and MG scale coincide at 33moa elevation angle, 1200m for HEAT, and 800m for MG. In the T-62's gunsight, it is similar, ~1230m for HEAT and 800m for MG. It is possible to match this and the 2m direct shot data closely only if I increase the air resistance value of the shell. And with those values, the max range of the 115mm HEAT shell will be close to 100mm, but will not reach it, despite higher MV and larger mass.

 

So, to sum up after all of this nonsense above, my questions are the following:

Is it possible that the real world air resistance of the 115mm is so much higher that at longer ranges, it will be slightly inferior to its 100mm counterpart despite higher MV and mass?

Is it possible that some of the data regarding the 3BK4 is incorrect? I actually found the 2m/990m direct shot range in the original manual of the 115mm gun, but not the 2.7m/1200m, which is mentioned only in non official sources. Same for muzzle velocity...

[Ssnake]

Not sure why I'm helping out for a competing product; it's aSaturday morning at 2 am and I have no life.

Or maybe it's just because I'm slightly drunk, and have done enough ballistic table approximations in my life that I sympathize with your big round eyes.

 

6 hours ago, old_goat said:

Is it possible that the real world air resistance of the 115mm is so much higher that at longer ranges, it will be slightly inferior to its 100mm counterpart despite higher MV and mass?

No.

6 hours ago, old_goat said:

Is it possible that some of the data regarding the 3BK4 is incorrect?

Yes: Jane's Weapons: Ammunition 2024/25 (formerly known as Jane's Ammunition Handbook) gives a muzzle velocity of 900m/s for the BK-4M projectile. I've never come across a different claim that I bothered to memorize. I hope that alone already helps to set you on the right track because I'm not going to generate a complete table for you.

[Stuart Galbraith]

I would have to go and track it down in 'The Archive', but I distinctly remember David Isby saying in Weapons and Tactics of the Soviet Army that the Israelis regarded the 115mm as highly effective, better than the 105mm below 1500metres, but say it wasnt as good for long range work. In particularly I remember something about the HEAT round (which was presumably BK4) being particularly ineffective for long range work. Weathervaning perhaps?

The question arises, how realistic the longer range engagements are, and whether it was more suitable for area targets due the inherent inaccuracy of firing a smoothbore.

Tradoc has some interesting tables which illustrates first round hit for a HEAT round at 1500 metres is 20 percent. Which suggests to me a certain amount of instability when its targets over 1000 metres.

https://apps.dtic.mil/sti/citations/ADA392790

Edited June 8 by Stuart Galbraith

[Stefan Kotsch]

It must also be noted that the ballistic values in question here do not behave linearly.

Simple extrapolation is misleading. Or just the fact that each shell has a different center point of impact. Without a computer it will be fun to shoot tanks.

[Ssnake]

I think the BK-4 doesn't offer very high precision, which in itself isn't going to be the main factor why it's largely useless beyond maybe 1300...1500m range; primarily it's the low muzzle velocity combined with a relatively high drag that requires a steep trajectory. Combined with stadiametric range estimation (only) the ranging error will quickly prevent first, second, possibly even third round hits. The drawing in JWA 2024 pg 427 suggests that the BK-4M projectile has a tracer element, but it's nowhere mentioned; let's assume that there is one, burning out to 1500m, and you have one more reason why you wouldn't use this for extended ranges.

[bojan]

37 minutes ago, Ssnake said:

I think the BK-4 doesn't offer very high precision,...

0.21 mils dispersion was batch acceptance standard for all Soviet smoothbore guns fired HEAT* (100/115/125). In practice it was 0.15-0.18 most often.

*For APFSDS it was 0.25 mils, for HE 0.23 mils.

 

[Stefan Kotsch]

It would be very surprising if the dispersion, for example,  of the 115 mm HEAT differed significantly from the 100 HEAT. An average of HEAT 100 and 125 mm is probably acceptable.

@ The manual for the 115 mm tank gun gives an effective firing distance of 1500 m for the HEAT when firing at moving targets.

Edited June 8 by Stefan Kotsch

[old_goat]

13 hours ago, Ssnake said:

Not sure why I'm helping out for a competing product; it's aSaturday morning at 2 am and I have no life.

Or maybe it's just because I'm slightly drunk, and have done enough ballistic table approximations in my life that I sympathize with your big round eyes.

A mod (that will never be published) for an ancient game that almost nobody plays anymore is hardly a competitor for you

13 hours ago, Ssnake said:

Yes: Jane's Weapons: Ammunition 2024/25 (formerly known as Jane's Ammunition Handbook) gives a muzzle velocity of 900m/s for the BK-4M projectile.

Thanks! I'll give a try with 900m/s, and see what the FT will be.

13 hours ago, Ssnake said:

I've never come across a different claim that I bothered to memorize.

Almost all russian sources state 950m/s. Although none are official. Thats why Im suspicious about it.

5 hours ago, Ssnake said:

The drawing in JWA 2024 pg 427 suggests that the BK-4M projectile has a tracer element, but it's nowhere mentioned; let's assume that there is one, burning out to 1500m, and you have one more reason why you wouldn't use this for extended ranges.

There is a tracer for the BK-4. Burn time is around 4-5 seconds as far as I know. (that is 2300-2700 meters for 100mm BK5 HEAT)

http://soviet-ammo.ucoz.ru/index/115_3ubk3/0-70

[Ssnake]

Cool, thx

[Stefan Kotsch]

We have the FT for the 100mm MT-12. That's a good reference. Because it is also a smoothbore gun.

For the 100 mm BK3 the initial speed is 975 m/s (but the drop in flight speed is dramatic). The 115 mm BK4 is heavier and the propellant charge is larger. I think for the 115 mm BK4 an initial speed of 950 m/s is realistic.

BK3: The dispersion (1/8) at 1600 m is 0.8 m in height and 0.4 m in width (125 mm 2A46 = 0.31 x 0.3) There is for the MT-12 a total of 6.4 m in height and 3.2 m in width. That's pretty large! This could possibly also apply to the BK4.

 

Edited June 8 by Stefan Kotsch

[old_goat]

I did more experiments with MV of 900m/s. It didnt work. Still impossible to match the 2m/990m and 2.7m/1200m direct shot ranges. Since the 2.7m/1200m isnt mentioned anywhere in official soviet sources, I think this is wrong.

But the good news is that I think I have found the solution. Meanwhile I did more digging, here is what I found:

First, muzzle velocity. It should be 950m/s. Stefan already explained it, and I fully agree with him but I provide little bit more details.
Weight of complete projectile is 12.53kg for 100mm BK5 and 13.2kg for 115mm BK4. The BK4 is slightly heavier, but it has significantly more propellant: 5,1kg vs 4,05kg. Weights come from official soviet sources.

Next step was the gun sight. There is a drawing in the manual for the 115mm gun, and while I stated above that drawings are useless, I just gave a try. I compared the drawing with a real photo of the TSh2B-32P sight of the T-55 in photoshop and surprise... MG and stadia rangefinder scales perfectly aligned! The 4000m mark for APFSDS also aligned perfectly with the 800m mark for MG, which is the same in the photo of the T-62M gunsigt. So that it is likely that this drawing is accurate after all.

And finally, I have some official data for maximum range of OF11 HE, 5800 meters at 16 degree gun elevation. I created a firing table for that in my program, and it matched the markings of the drawing of the sight. (to 3000m of course)

And with all of this data I think I was able to create a roughly accurate FT of BK4 and OF11 for gaming purposes. Conclusion is that at long ranges, 115mm BK4 has indeed slightly worse ballistics than 100mm BK5.
Probably thanks to the higher drag of the fins and larger cross sectional area of the projectile body. Higher MV does not help. And one more thing, In my opinion, the 1200m direct shot range for 2.7m high target is probably wrong. Totally impossible to achieve that with all of the data above.

I attached the images I used for this. First is page from 2A20 manual, second and third are from a now deleted video about the operation of TShSM-41U sight, fourth is an image where I overlapped a real photo of TSh2B-32P reticle on the first drawing, MG scale is perfectly matching, stadiametric rangefinder also (although its a bit hard to see). Main aiming mark also overlaps, but while the auxiliary marks do not, I think this is caused by some stretching of the picture. 

I hope all of this will be useful for somebody. Or maybe its total BS. 

 

Edited June 9 by old_goat

[bojan]

4 hours ago, old_goat said:

...Probably thanks to the higher drag of the fins and larger cross sectional area of the projectile body. Higher MV does not help. And one more thing, In my opinion, the 1200m direct shot range for 2.7m high target is probably wrong. Totally impossible to achieve that with all of the data above.

At what distance it's speed falls bellow speed of sound? Blunt nose + probe HEAT exhibits some additional instability at transonic speeds, which leads to more rapid velocity loss in the transonic area that when it is flying either supersonic or subsonic.

[old_goat]

16 minutes ago, bojan said:

At what distance it's speed falls bellow speed of sound?

According to my calculations, at around 2540 meters. Which is almost the same as the 100mm BK5. But it isnt too relevant, since these are not blunt nose+probe type projectiles. But as for the later BK15, it is evident that it has significantly improved ballistics.