According to historical sources, Italy’s 381/50 guns were comparable to the U.S. 406 and the Japanese 460.
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Oh wow this thread went a fair bit further than I’d have thought.
Now that I look at this, the penetration for Roma’s AP shell with a regular PenetrationK of 1 does seem a bit high, but still, the formula was meant to standardize these things. As far as I can see we still haven’t gotten a proper answer as to why the coefficient isn’t 1, but if it’s because of limitations of the calculator, then I wonder just how many shells “break” the calculator.
Anyways, I do want to show some things about Soyuz’s SAP.
If we once again try to use the calculator (just for demonstration purposes), we can see that it stops working at 44.4kg of filler, so about half the actual filler. That is, at filler weights higher than 44.4kg, the shell stops losing penetration (I’m guessing this limitation is part of the reason that K coefficient exists).
Still, Soyuz’s SAP shells still get a K coefficient of 0.87. So we get a near 100% increase in filler, but only a 13% decrease in penetration, which is kind of insane!
And Roma’s SAP does still work as is in the DeMarre calculator (and gives a point blank penetration of 728mm). It only stops working with a 33kg filler. 728mm does seem pretty high for a SAP shell but cutting nearly half its penetration is very harsh. Again, that’s just for the sake of comparison, 99% of SAP shells don’t fully adhere to the calculator.
[you can ignore the following, I’m not that confident in my results, it’s not that serious]
I did a silly little experiment, and scaled up Roma’s SAP shell to 16in while maintaining the C/M ratio and the 0.55 K value.
Shell weight → 824.3*((16/15)^3) = 1000kg
Bursting charge → 29.52*((16/15)^3) = 35.83kg
The shell ends up with 430mm of penetration at point blank, still far less than Soyuz, yet with less than half the filler!
Now of course, the Italian 381mm SAP did have that peculiar dual fuse, which does take a non-insignificant amount of space, and some weight, but it’s hard to believe that’d be enough to cripple its penetration.
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I think Roma’s SAP shell is still heavy WIP as it underperforms even the 320mm one from Cavour and Duilio. ( and it almost weight double those shells and have higher muzzle velocity)
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Nobody has mentioned that the devs generally tie dispersion (maxDeltaAngle and maxDeltaAngleVertical) to barrel length, so it is a bit unusual for the 380/45 on Richelieu to have the same dispersion as the longer 381/50 guns on Roma.
Both probably should have better mechanical accuracy, but the devs do as they wish for this sort of thing. Anyone who has used the British 381/42 will know the experience of using huge inaccurate shotguns that aren’t exactly historical.
Italy being singled out for having artificially higher dispersion is not new unfortunately. Remember when Gaijin finally adjusted dispersion for all other ship cannons to finally be accurate? Yeah, Italian 320mm was the only one who had higher dispersion patterns to deal with.
Its strange, if Roma was given a monsterous pen for a 15" the abysmal 1.3rpm could be sorta understandable, not good and still very unfair but you can see the logic. But Gaijin choosing this strange worse of both worlds option is puzzling.
I will also remind that in War Thunder her armor and survivability is nothing special, every other big gun can easily deal with her making her a bit of a glass cannon. So in gameplay terms, a very effective gun would go wonders in establishing a niche to make the Italians heavy hitter in NRB.
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To add something more to dispersion. during the battle at Cape Spartivento, Vittorio Veneto fired from a really long range (28.5-32.5 km) at HMS Manchester. The fifth and seventh salvos were on target. The shells fell really close to the ship.
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