15cm KwK 44 L/38

[Tenkist]

The theme of this post is 15cm KwK 44 L/38 gun proposed for E100 heavy tank.



As we can see on the graph AP shell weighed 45kg and was fired with a muzzle velocity of 740m/s

I am interested in what type of projectile was used.
I found two similar projectiles.
A.P. Projectile, 150-mm, 15-cm Pz.Sprgr. L/3,7 m.Hb.

http://michaelhiske.de/Allierte/USA/TMa ... ig_493.htm

15-cm Pzgr. L/3,7 m.Hb.

http://www.navweaps.com/Weapons/WNGER_59-60_skc25.php

There are some difference, for example in weight.

I also met another designation 15-cm Pz-Sprgr L/3.8

http://www.lonesentry.com/articles/ttt0 ... -guns.html

[critical mass]

The 15cm L/3.7 Psgr m. Hb. is an old naval APCBC-HE, developed during ww1, abandoned in the 1920´s and reintroduced in the mid1930´s.

[seppw]

reminds me of the russian 122mm/152mm guns.
low mv -> poor fineness -> poor accuracy
mediocre penetration for its calibre
big and heavy -> difficult to integrate
heavy shells -> poor rate of fire
Good on them for not fielding as an (anti-)tank gun. A very impractical (anti-)tank gun, just like most ww1 naval guns.

[critical mass]

attached the penetration graphs of 15cm Psgr L/3.7 against ductile and soft, naval homogenious armor (Wh/n.A., ca.80kg/mm² tensile strength) for the usual standarts (5/5 successful attempts in a narrow velocity band). A significant advantage of the L/3.7 was that against homogenious armor, it regularely stayed intact and didn´t broke up even at high obliquity. Not sure if this would hold true vs harder armor, too.
Penetration at 60° and 700m/s was roughly 0.49 times those of 30° which compares favourably with, f.e. 128/88mm Pzgr Ts = 0.40 at 1250m/s, 88mm Pzgr39/43 was 0.42 at 1000m/s and 75mm Pzgr 39 = 0.44 at 850m/s.Against less ductile armor, this would considerably increase due to shear effects.

[Tenkist]

Nice. Very similar penetration results, but 0.5kg weight difference.

[Chupacabra94]

Am I right in understanding no 15cm KwK 44 L/38 was ever completed? Panzer Tracts 6-3 contains this small paragraph. With 'gun tubes' do they mean only the barrel or a complete breech-barrel assembly? Otherwise I would guess the complete ones could be rifled and the incomplete maybe still be smooth, something like that?

[Tenkist]

I think that if the graph contains data about this gun then it had to exist and be fully functional.

[critical mass]

Not necessarely. The penetration depends first and foremost on the projectile and it´s charackters. The gun is just a mere medium of accelerating the projectile to a given initial velocity. The projectile then takes over and loses velocity downrange due to drag.
The exact ratio at which velocity is lost for a given projectile has been well studied at this point. The 15cm Psgr. L/3.7 was the primary APC projectile for Navy applications and full sets of penetration and ballistic curves had been worked out for this projectile.