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I understand why it was necessary to complicate the design in this particular case (for use of standard large caliber ammunition), but with AT guns, why? Artillerymen will have to either jump into a trench or run a decent distance away from the gun every time it is fired.Quirk with this system is that one still uses the off-the-shelf ammo.
RT-20 was supposedly doing 850 m/s, despite the short barrel and the divertion of small % of the gasses.
British weren't able to examine newer armor from the USSR before the choice was made to deply all the various *BAT HESH tossing recoilless guns.But the Germans used heterogeneous armor with a medium hardness backside, and the Soviets used medium hardness armor (42SM, 52S) after the war.
Armor penetration is a subject so complex that even different modern computer models can't always agree on results. A projectile moving at 2500f/s and penetrating 4-in of armor all happens in 13 MICRO-seconds (.00013 sec, or thereabouts.) Macroscopic (Newtonian) things happening in this short amount of time can give results that are almost impossible to predict with certainty. There's shock waves bouncing around, melting of both the projectile and target due to kinetic energy transforming into to thermal engergy, unequal forces on the projectile and target, etc. There are numerous "formulas" for amor penetration that can be modeled (PRODAS, Thompson, Lambert-Zukas, etc.) and all their outputs will vary with different materials on both the target and projectile. The best you can do is predicting "roughly" what will happen, or should happen. Google a copy of AD1045347 (PDF, 2018) for information on the WWII 76mm Sherman tank gun vs Tiger/Panther using modern "computer models" to get an idea for how complex this subject is. Hat's off to you, though. Your studying this subject is highly admirable, and "you will never have to prove your courage to me in any other way." Post anything interesting you find (or calculate.)I'm still studying armor penetration - trying to understand how much the caliber of the projectile mattered, and how much the design of the projectile mattered for different types of armor and different thickness. Soviets used homogeneous armor of high (or very) hardness, even late cast Soviet armor was high hardness, Germans used heterogeneous armor (with rare exceptions at the end of the war), Americans used medium to low hardness armor with a high proportion of cast parts, etc. In some cases APCR was optimal, somewhere only a high hardness cap was sufficient. In addition to armor properties, the ratio of core size and armor thickness mattered. All this is time-consuming, but I still want to get some kind of overview for myself.
Some of the things that came across during my research: scans of Soviet reports (terrible quality, unfortunately) on tests in early 1942 of 45mm APCR with different core materials and different projectile design, but the same geometry for each core material (tungsten carbide or high-hardness steel). It turned out that I was wrong: steel cores demonstrated much worse armor penetration and were never mass-produced - they were even banned from further testing.
A projectile with a more massive core had higher armor penetration but worse accuracy and was rejected.
When German shells were fired from a Soviet 37mm anti-tank gun in 1941, the armor penetration was superior not only to the original Soviet shells but also to that of Soviet 45mm shells.
Also, HESH did double duty as a HE round and was used as such - eliminating the need to carry an additional type of ammunition.
The countries that adopted HEAT rounds either carried dedicated HE rounds in addition to the APDS and HEAT - or developed HEAT/MP rounds to be used as a bit sub-par HEAT and HE.
It might indeed be an error.It could be error.
Getting 100mm of penetration out of a 70mm diameter war head/shell is defiantly in the upper reaches of shaped charge penetration in WW II.
And 70mm is being generous.
Looking at the kwk 37, that fired the HEAT shell at even lower MVs, that one was good for 66% chance to hit (a tank-sized target?) at 1000m, and 99% at 500m. FWIWThe PAW 600 is generally rated as having a 750m effective range, which is still a sort of arched trajectory.
A gun that split the difference in velocities might have an effective range of 600 meters or a bit less.
I'm just wondering how this howitzer with weak ballistics (almost mortar-like) could hit a moving tank at a distance of more than 50m?A gun that split the difference in velocities might have an effective range of 600 meters or a bit less.
I'd suggest not being too trickyGranted a WW II version may use a bit more gun and bit less rocket which might reduce this tendency a bit.
It is possible to use a rifled tube and fins and this, while more expensive, may keep the round steadier in the first few dozen meters while speed builds up. May also mean you can use shorter fins?
A lot depends on just how tricky you want to be.
Thank you for this - I was aware of the 'Cockelrill' gun and Mecar rifle grenades, but this is new to meNow things get real confusing as Mecar offered a longer, heavier, higher velocity 90mm gun and ammo. The Cockrill company offered both short and long 90mm guns and a French company also offered a short/light 90mm gun for armored cars which used similar but not interchangeable ammo. The French gun is a smooth bore.
Or the early HESH the Italians used, EP 'Effetto Pronto'How low might one go and still have a satisfying light AT gun that uses HEAT?