Its 663m/s.
I haven’t found historical FT for this gun, but I’m confident in this estimate.
Yes, I took the values of the german G(d) limit shown in the graph I posted from this very source.
The German data for 5cm shells is odd. The capped shell should have only 3.4% higher ballistic limit if we only take into account its lower mass (sans the cap). 460m/s - > 476 m/s.
It’s hard to believe that the added small cap (6% of total mass) increases this bl to 510m/s, a 7% increase. The data on US testing with M51 APC with and without cap shows a much smaller increase of about 2% at all t/d ratios. But this is at 0°, maybe at 30° the AP cap is more detrimental.
Using my suggested changes and the standard slope modifiers, at 663 m/s it would penetrate about 35mm of armor at 30 degrees.
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Your conclusion in your final comment matches what the game has, where cast armor receives a 0.94x multiplier to it’s thickness compared to RHA.
Surprisingly. With so many other things that Gaijin got wrong, I didn’t expect things to match so well. But I am not complaining.
I recall discussions that cast armor gets closer in effectiveness to RHA the larger the plate is. No clue about the evidence behind it though.
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Yeah that was stated in “WW2 Ballistics: Armor and Gunnery”.
Yes, however what real life testing did they use?
No clue. I think they just came to that conclusion, probably based on same US test.
But considering that the authors had the habit of coming to wrong conclusions, I wouldn’t be suprised if there was no concrete evidence.
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On the topic of shatter and “capped” penetration of uncapped AP. It would look something like this:
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What’s kinda funny is that WT got more and more advanced, e. g. composite armor and missiles with infrared and radar seekers, countermeassures and notching etc.
Yet good old aircraft cannons and regular AP rounds are just so basic that almost nothing makes sense.
I mean how does it make sense that we have modern tanks with composite armor but not a single tank that has face hardened armor?
Or that HHA is just a better armor type than RHA at all cicumstances. They can’t even declare T-34s armor as HHA or everyone would just call out Russian Bias.
APFSDS bounces from Abrams upper glacis into the neck but T-34 driver hatch stops a Panthers 75mm from point blank.
The game just goes forward but doesn’t really care about the things that are already in the game.
Only when they add something new that affects older vehicles, something changes.
What makes me laugh is the naval devs will adjust the penetration formula to match historical performance but the ground devs won’t.
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I’ve noticed how chill and polite are naval players on this forum. That explains it.
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Chart for the 75mm M3 and M6.
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Your estimate for the penetration of M61 is a bit high. The mass of M61 APC filled and fuzed without counting AP cap and windshield is 5.67kg (12.5lb).
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@MiseryIndex556 Check this out. Looks pretty neat, right?
QF of 0.9 - 1.0 can be used for capped solid shot, 0.8-0.9 for APCBC-HE, 0.7-0.8 for uncapped solid shot, 0.7 and below for uncapped APHE.
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That sounds like a (way too much) broad simplification.
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I was also thinking about a way to nerf the 88mm Pzgr.
At the moment it is hardly worse than the 88mm Pzgr. 39. The only thing making it worse is the amount of filler, since KE is more or less the same.
→
As we can see, there’s quite a difference between the 88mm Pzgr. and the 85mm BR-365.
Even though they have almost the same filler content, the 85mm has a lot more “meat” above the cavity.
And with meat, I mean steel 😂
Not sure, if there was a univeral way to change it. But one issue with Gaijins penetration calculator is certainly that Gaijin doesn’t consider the cap weight.
Like the APC modifier turns an AP shell into an APC shell of the same weight with more penetration, even though for that to happen, the penetrator must be smaller to make up for the weight of the cap.
In this case both 88mm Pzgr. and 85mm BR-365 get around the same reduction for filler, even though the 88mm Pzgr. penetrator integrity is obviously reduced by a greater amount, as seen by the picture.
I guess one factor that is also not considered is the massive fuze, that adds weight to the shell but actually makes the shell weaker, requiring an even greater cavity to fit.
It’s crazy but the fuze for the 88mm Pzgr. weighs a whooping 950g with tracer, compared to the Pzgr. 39 fuze, which weighs merely around ~333g.
What’s interesting is that the 128mm Pzgr. and Pzgr. 43 are pretty much the same design as the 88mm Pzgr., having an enormous cavity but the fuze for the 128mm is actually much smaller, weighing merely 124g without tracer and detonator.
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