APDS now shattering on IS-3 track armor

Machinery of War Discussion Ground Vehicle
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Issue is that some of these 17pdr figures were tested using a Firefly which may not be the best means to test the gun. Im not sure exactly what the issue was regarding the accuracy but for some strange reason the Comets 77mm gun which is very similar to it but unfortunately less powerful, was noticeably more accurate and more on par with your average tank gun in terms of accuracy. I was thinking that maybe the ammunition fired was too powerful but I think the comet fires the same ammo and propellant unless im wrong. Maybe some issue with the breach. I dont know how tank guns work, just spitballing.

Someone should if he hasnt answered already ask the chieftain why this is the case, as he has done some content regarding the accuracy of the 17pdr weapon and deemed it probably good enough for the engagement ranges of WW2. That is reflected in the game at least where it is accurate enough that you wont literally miss a target you were aiming at.

It should be noted that Russian guns during this period were not regarded as particularly accurate either, it wouldnt surprise me considering the frequency of overweight, oversized shells and comparatively short barrels to sling them, as well as notorious manufacturing doctrine.

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I also read something similar, that the tests were using a Sherman Firefly, and that the sight did not have the references for the APDS, so the shots would be by eye.

What he shoots is the same bullet, but the casing is different and carries less propellant, which is why it did not have the same bullet speed.

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That would make more sense than the slightly shorter barrel resulting in the 25% or so less performance.

So the issue was the propellant most likely, it also explains why the APDS is more accurate on the Comet if the muzzle break is the issue. Maybe its those two factors combined that made it so inaccurate.

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On one page I read that, that it was a problem with the friction bands of the APDS, when firing the first shot, pieces remained inside the barrel, so the second shot would deviate, and an APCBC would have to be fired to clean the barrel .

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It’s not “one shot” it’s firing loads that caused fouling, modifications to the muzzle brake came swiftly to fix said issue.

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This is an issue with basically every weapon yes, they had to issue instructions for how to overcome this problem, something like set to 1/2 up to a certain range then 1/3

Chieftain only had one source for the whole inaccuracy thing anyway, and it is very CLEARLY due to a bad batch of ammo, the American documents say the British claim this, the British documents show it too. Bear in mind that test was done months before general issue.

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@poopooo @XreGenerations
I believe the difference in accuracy with APDS between 17pdr and 77mm guns, could be explained by the different rifling twist. If the rifling twist in the 17pdr (1 in 30 cals) was insufficient to stabilize the APDS shell, then perhaps the one in the 77mm gun was. But I was unable to confirm it, as the technical information about that gun is scarce.

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I don’t know in reality what exactly the precision of those cannons was, but from what I have been able to see, in the game those cannons have been modified to have poor precision, which, added to the fact that they are Full AP, makes them horrible cannons. Now I’m playing with the concept 3 myself and the cannon is a disaster, it has a lot of problems destroying tanks, while with the Churchill NA75 with its APHE it is much more effective against any tank, despite having 50mm less penetration, a real shame the work that gaijin has done with the tanks with Full AP.

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I like the music

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Techno Kitten Adventure Theme - Sea of Love

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ty

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I don’t believe 77mm uses a different twist rate, neither were optimised for subcalibre but by the time 17pdr APDS was being recieved by troops accuracy was sufficent. I have an excerpt here from July 1944 where an in field unit 259 Bty. find Sabot a complete success, and Gunner hit a 2 inch square of white paper at 700 yards, something I doubt you could manage in game (and this is very early in 17pr APDS service). Actually in game both 77 and 17pr have some of the worst accuracy of guns at their BR, the Russian 85 is far more accurate.

The whole 17pdr innaccurate nonsense is because pre serial production rounds at the March 44 Shoeburyness trial were used that either A were a bad batch or B gunner was overcorrecting the lay (sights didn’t have APDS graticules at this point), then the US reports (which the Chieftain quoted) write the rounds off as terribly inaccurate. To quote Ordnance Board investigation No 659

As however a number of misses were obtained and there seemed to be difficulty overcorrecting the lay at round 8 it was decided to change to a new lot (Mackie’s lot 3) which had passed a satisfactory accuracy proof.
After this change had been made no further misses occured with D.S 17-pr. though some of the strikes were on tracks, bogie wheels, etc, and could not therefore be considered lethal.

Either way accuracy improved over time.

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Can you post that?

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17pdr Accuracy APDS 257th battery balleryo test commented

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I did slightly drag things off topic but to get back on topic yes this is unbelievably frustrating, Gaijin have taken a real problem, then magnified it massively out of proportion. IE IRL problem, 6 pounder APDS was found to sometimes shatter on Tiger Is lower side after having passed through the multiple thick steel road wheels. But Gaijin makes this problem occur wiith 17pr APDS and even much more powerful ones like the 20pr and 120mm L1. Then as in this case, even mild steel tracks pressed against the armour wildly increase protection.

Realistically APHE fuzing too early/not at all is going to give you more problems than this but Gaijin havn’t modeled that kind of unrelability because it percludes fun. So it’s baffling why they decided to do it in this case. Why not add gearboxes engines breaking down on their own too, make everyone a bit more miserable!

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Thanks for the clarification, I remember that I read about the poor accuracy of the APDS of the 17pdr, and that it was due to the lack of sight for that ammunition and something related to the friction bands of the bullet, but what you have put here clarifies everything .
As I said before, I am playing with the concept 3 and its 77mm, and it is a real disaster in precision and damage, the same thing happens to the 17pdr, having a horrible precision at more than 300 meters, making precise shots very difficult in weak points of the tanks.

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Gaijin really should thoroughly review the game and its mechanics, it cannot be that there are cannons with poor precision because someone thought of it randomly, for example the 90mm cockerill cannon has by far the worst precision I have seen in the entire game A KV-2 or a Brummbar being much more precise. On the other hand, returning to the subject of the British, it seems horrible to me that they give the precision through tests of almost a prototype, and they will not be guided by combat tests, and more even having Full AP ammunition, which makes it a real pain to play with the British tanks, and all so that players with APHE have fun killing, simply something painful on the part of gaijin.

Haha, I think that could also be said the other way around with the T-34 and KV-1, since they withstood brutality against 50mm and 75 short cannons, they have been given somewhat exaggerated resistance, since the T-34 and KV -1 They should be relatively easy to drill through the 75mm KWK 39, however in the game they often stop the 77mm and the 17pdr without problems and only because they are slightly to the side.

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I hated using the Concept and quickly ditched it, solid shot is so reliant on velocity to damage hence 77 does noticably less than 17pr. It’s extrodinarily noticable on OQF 75mm solid shot, it is lucky if you kill one person with it. That is real though to an extent, that’s why on medium velocity guns like 75mm M1897 make more sense to use APHE, slow moving shot does less damage.

Going in to the data mine to check accuracy: This shows 17pdr is absolutely less accurate than it’s contemporaries in game, the closest equivilent in power is the 90mm and 7.5cm Kwk 42 yet those guns have almost triple the accuracy.

Spoiler

90mm M3:
“maxDeltaAngle”: 0.027,
“maxDeltaAngleVertical”: 0.027,

85mm D5T:
“maxDeltaAngle”: 0.027,
“maxDeltaAngleVertical”: 0.027,

Kwk 36 (short 88):
“maxDeltaAngle”: 0.027,
“maxDeltaAngleVertical”: 0.027,

76mm M1:
“maxDeltaAngle”: 0.027,
“maxDeltaAngleVertical”: 0.027,

75mm M3:
“maxDeltaAngle”: 0.075,
“maxDeltaAngleVertical”: 0.075,

75mm M6 (M24s gun):
“maxDeltaAngle”: 0.07,
“maxDeltaAngleVertical”: 0.07,

7.5cm Kwk 42 (Panthers gun):
“maxDeltaAngle”: 0.027,
“maxDeltaAngleVertical”: 0.027,

Kwk 40 (Panzer IV F2/G etc):
“maxDeltaAngle”: 0.07,
“maxDeltaAngleVertical”: 0.07,

77mm HV:
“maxDeltaAngle”: 0.075,
“maxDeltaAngleVertical”: 0.075,

17pdr:
“maxDeltaAngle”: 0.075,
“maxDeltaAngleVertical”: 0.075,

Gameplay wise this is a serious hassle because whether you’re using things like Avenger against Panther front or Centurion Mk 2 against IS-6s front the ability to hit weak spots is the only way you can possibly survive. Basically all British vehicles til 8.0~ are terrible snipers because you need good damage for sniping to work and solid shot can’t do it. Snipe off against a Panther even when you do hit weak spots will take 4 penetrating hits to kill. The fact the gun lacks in accuracy does not help this fact.

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Ahh, I seriously hate gaijin more and more, the fact of having a game that is basically great and wasting it by not doing the job well is something that drives me crazy.

Yes, but I imagine that apart from the speed, the penetration will also be an excess of damage factor, if you shoot with the 75QF that pierces 103mm, an 80mm plate still has 20mm of penetration left, so the fragments that will still have some kinetic energy will still have some kinetic energy. enter the tank, although yes, it is clear that a 77mm and a 17pdr will do more damage because those fragments will be pushed at a higher speed inside the tank, but in any case human flesh is not resistant hehe.

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That’s the case because the accuracy on those guns was bug reported with test data on their real life accuracy. Multiple rounds being fired at targets to determine the real life deviations.

If you want the 17 pounder getting better accuracy, doing something similar is probably the best bet.