Characteristics of the French 100mm SA47

Does anyone have any information or documents on the penetration of the French SA47, especially at an angle?
In the game it can’t penetrate even T-54 UFP, but I don’t believe that a gun designed to fight Soviet tanks and firing a 15 kilogram shell at 1000 m/s can’t penetrate its main opponent.

It’s what I can find. It’s pretty much the same design as the 75mm POT-51 round. Currently, in the game, it’s classed as APCBC, when it should be an APBC round.

French 100mm AP-T

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Is this by any chance a document from the AMX-50 trials in America?
I have heard that at least one tank passed them in Aberdeen.

So the 100 mm AP round is classified incorrectly and also weights about 1 kg too little?

With it being APBC and weighting 16.08 kg, this would be the new penetration value:

Spoiler

image

I’ve estimated the slope penetration at 60º and came to 96 mm, compared to the current 91 mm. Still not quite enough to punch through the UFP of a T-54, but I imagine that might in part be due to the calculator and the 0.9x multiplier that uncapped AP gets.

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Here’s my estimate for it

Considering that
90mm M77 AP could defeat 191mm of RHA at 822m/s , M318A1 could defeat 222mm of RHA at 914m/s and considering that the US 76.2mm AP could defeat 160mm of RHA at 792m/s

The French 100mm APBC would have
298mm @ 0m (0) of Penetration.

If we use Japanese late ww2 AP quality then 278mm @ 0m (0)

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To calculate penetration at 60 degrees where non capped AP rounds do not deform whatsoever we will use British 2 pounder AP as reference which has penetration stated without deformation. In order to calculate 60 degree value correctly we cannot use the 0 value after deformation since deformation doesn’t occur at 60 degrees

40mm AP, 1.08kg penetrator at 792m/s
90mm of RHA penetration.

100mm APBC without the ballistic cap has penetrator weight of roughly 15.65kg

If the 100mm APBC round didn’t deform against flat thick armour whatsoever, the penetration would be 318mm. This is why we will use “318” value because at 60 degrees like I already mentioned, AP rounds don’t deform. However if we used the 0 value after the round deforms, it would mean that we would be treating the AP round like it does deform at 60 degrees as well when it doesn’t.


AP Slope Modifiers

The 100mm APBC would have
115.7mm at 60 degrees of penetration

At 1.157 T/D ratio the slope modifier is 2.75 at 60 degrees. 115.7mm x 2.75 = 318mm at 0 degrees

Conclusion:
278-298mm @ 0m (0 Degrees)
116mm @ 0m (60 Degrees)

Obviously not as good as 120mm M358 APBC with 135mm at 60 degrees…

Oh and here is the US WW2 AP penetration

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With the way gaijin calculates all AP rounds in the game

You got
258mm @ 0m at 0 degrees
96mm @ 0m at 60 degrees

When in reality the accurate penetration would be
278-298mm @ 0m at 0 degrees
116mm @ 0m at 60 degrees

So with the way gaijin would calculate this round we would get values that are:

7.8%-15.5% underperforming at 0 degrees
20.8% underperforming at 60 degrees

On top of that by changing it to AP round, the chance of bounce will be 50% at 60 degrees which is also BS and 100% chance of bounce at 63 degrees which is utter BS as well.

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Great job. One question, could you do the same with the 90mm ammunition from the ARL-44?

Just give me all the details for the round

Uff, I only have the data of the same game.
90mm
10.74kg
1000m/s
And its APCBC.

I personally don’t use APCBC slope modifiers because whenever I use them, they just never match the real life test results but when I use AP slope modifiers for APCBC rounds then I get more accurate results.

According to British Report M.7000 A/11 No.1 , Department of tank design armour branch.

According to the Brits, as long as the penetrator size of AP and APCBC round was the same, the sloped penetration was the same. Although the APCBC needed little bit extra velocity to compensate for the ballistic cap and piercing cap getting in the way before the penetrator digs in why which then it losses some of its impact velocity

For example

20 Pounder APCBC
???mm @ 1000 yards (0) - 930m/s
173mm @ 1000 yards (30) - 930m/s
113mm @ 1000 yards (45) - 930m/s
90mm @ 1000 yards (55) - 930m/s
76mm @ 1000 yards (60) - 930m/s

233mm @ 1000 yards (0) with APC(BC) slope modifier calculated from 60 degree angle.
It’s far too high

202mm @ 1000 yards (0) with AP(BC) slope modifier calculated from 60 degree angle
I get realistic value since 20 pounder APCBC only had roughly ~230mm at point blank range

This is just 1 of the many examples which made me abandon the APC / APCBC slope modifiers completely and the British conclusion makes more sense to me

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I imagine that what you say is correct, since the protective cap did not have the function of improving penetration in inclined armor, it was created so that the tip would not break on impact with hardened armor at 0º, and like the explosive filler, They are nothing more than remains of the design from which anti-tank ammunition started, which is ship ammunition, bullets that needed a cap to be able to pierce the hardened armor of battleships and have explosive filler to cause fires and internal damage in the large number of interior space of a boat. That is why the more the ammunition advanced, the cap and the explosive filler were stopped being used as in the French ammunition or the M103, M48 and M41.

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I believe the APCBC classification is incorrect.

Gaijin seems to have wrongly given the 90 mm SA45 (cannon used on the ARL-44) the 90 mm PCO-50 APCBC round, when actually only the SA47 (cannon used on the AMX M4) used this round.

On the old forum there’s a topic called “Catalogue of French Armament and Ammunition”. In it there’s the ammunition specifically used by the 90 mm SA45 cannon. Here’s the link if you want to check for yourself.

90 mm SA45 information from the old forum topic

90 mm Obus de rupture “magnesium” (APBC-I)

FohQvxA.jpeg

Standard ammo for the SA45. capable to penetrate any tanks of his time. the round was made with a ballistic cap made of Magnesium who provoke a flash and incendiary effect on impact. this incendiary effect was having for purpose to allow the crew to know where they hit.

projectile weight : 10.60 kg

projectile velocity : 1000 m/sec


90 mm Obus de rupture “steel” (APBC)

Standard ammo for the SA45. capable to penetrate any tanks of his time. the round was made with a ballistic cap made of steel who was making it heavier and penetrate a bit more. but it lose this incendiary effect who was allowing the crew to know where they hit. it was the exact same as the magnesium version.

projectile weight : 11.20 kg

projectile velocity : 1000 m/sec

In short, the 90 mm SA45 on the ARL-44 actually would fire an APBC projectile that weights 10.6 kg or 11.2 kg, at 1000 m/s.

There’s also an APDS round but seemingly it has poorer performance.

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17 Pounder APCBC
76.2mm, 7.71kg projectile
189mm penetration at 884m/s

We will use this as reference

French 90mm APCBC at 1000m/s would have 239mm at 0 degrees and 89mm at 60 degrees with AP slope modifier

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In that case

French 90mm APBC
11.2kg projectile
10.9kg penetrator without ballistic cap

If it didn’t deform at 0 degrees whatsoever it would defeat 275mm at 0 degrees at 1000m/s. We will use “275” to calculate penetration at 60 degrees since at that angle AP doesn’t deform.

Now if the 90mm APBC is same quality as US M77 AP the penetration would be 258mm at 0 degrees at 1000m/s after deforming. If it was Japanese WW2 AP quality then it would have 239mm at 0 degrees after deforming at 1000m/s

Conclusion:
239-258mm @ 0m at 0 degrees
100mm @ 0m at 60 degrees

To be honest, if all AP rounds were implemented correctly, the armour of IS-3 and T-54 wouldn’t be so overpowered. T-54’s would be far more penetrable and wouldn’t need to be 8.0BR

With this round you’d be able to yoink that T-54 side armour of 80mm at pretty extreme angles. You could easily punish a T-54 if he isn’t facing that hull at you enough plus the turret would actually be even easier penetration target.

But even if gaijin did fix the penetration the next issue will still remain…
50% chance of bounce at 60 degrees. Like what?!
100% chance of bounce at 63 degrees….

AP rounds could penetrate armour sloped at 70 degrees without bouncing if they have enough penetration.

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I chose to use the reduced vertical pen value since non capped AP shell start to deform more the higher the velocity and since these a rounds are at least 1000m/s, it’s only logical

75mm SA50 APBC
Penetration:
194mm @ 0m (0)
82mm @ 0m (60)

90mm SA45 APBC
Penetration:
239mm @ 0m (0)
100mm @ 0m (60)

100mm SA47 APBC
Penetration:
278mm @ 0m (0)
116mm @ 0m (60)

120mm SA46 APBC
322mm @ 0m (0)
135mm @ 0m (60)

French tank BR after penetration fix

Tier 2
Crusader II - 2.7
M3A3 - 2.7
CCKW 353 AA - 2.7
B1 Ter - 2.7
M4A1 - 3.3
M4A3 (105) - 3.3
M4A4 - 3.7

Tier 3
M10 GMC - 3.7
ACL-1 - 3.7
AMX-13 (FL-11) - 4.0
EBR (1951) - 4.7
AMX-13 DCA 40 - 4.7
M4A3E2 - 5.0

Tier 4
M4A1 (FL-10) - 6.0
M4A4 (SA50) - 6.0
M36B2 - 6.0
ARL-44 - 6.7 (Also fixed reload speed)
CA Lorraine - 6.7 (Aldo fixed reload speed)
ELC Bis - 6.7
AMX-13 (SS.11) - 7.0
AMX-13 (SA50) - 7.0
AMX M4 - 7.0

Tier 5
AML-90 - 7.3
Char 25t - 7.3
AuF1 - 7.3
Lorraine 40t - 7.7
AMX-50 (TOA100) - 7.7
AMX-13-90 - 7.7
AMX-50 Foch - 7.7
AMX-30 - 8.0
AMX-50 (SA46) - 8.0

Tier 6
AND SO ON…

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Using the modified calculator I’m suggesting, the 100mm would have 310mm of penetration.

IMG_6307

Sorry but no because if that AP didn’t deform it would do 318mm.

At point blank range the round is hitting steel plate that’s 3x thicker than it’s diameter with 1000m/s impact velocity.

It’s vertical penetration is going to suffer from deformation and it won’t be only by measly 8mm

I’m not taking deformation into account, so that isn’t relevant.

Also, I used T33 navy pen charts as the reference for my calculator suggestion. Even then, 8mm difference above 300mm pen is minor.

Can I see the source? I never saw that schematic before.

Thanks to everyone who participated in the discussion. Since I created this thread, I was able to find actual tabulated penetration values for 100mm and 120mm guns. What is interesting is that they are almost identical to the figures given above by @Sombralix.
100mm
120mm

Correction, the penetration for the 120mm seems to be listed for the APCR

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