#94
Post
by critical mass » 13 Dec 2018, 13:26
German 50mm full calibre AP ammunition.
I) 5cm Pzgr. Patr.38, AP-HE
Monobloc AP-design without AP-cap and windscreen. With small HE filler and delay action fuze. Standart AP projectile for all 50mm guns until spring 1942. Thereafter still used when MQ target plate was to be defeated by KWK38 (5cm L/42) guns.
This projectile was prone to break up when engaging 1.2 cal MQ/RHA (take into account the elevated hardness at this thickness range) at 30° obliquity, resulting in loss of penetration, despite increase in velocity.
This projectile was prone to shatter when engaging high hardness, homogenious armor of about cal/t or face hardened armor, particularely at close range.
II) 5cm Pzgr. 39, APC-HE
composite type (with welded on tip) with AP-cap but without windscreen. Same filler and fuze as I) above. While designed in 1939, the mass production only started late in 1941 with deliveries commencing in spring 1942 in quantity. This projectile had a slightly lower penetration than the AP mod.38 above under conditions where no projectile damage was occurring to both shells (the cap gets wasted). However, it was resistent to shatter at > muzzle velocity for the PAK38 and did not experience break up until >1.5cal face hardened or high hardened armor was attacked, which allowed increaed penetration at elevated velocities without the projectile to suffer break up. Later received improved heat treatment and fuze design.
This projectile sacrificed some long range for increased short range penetrative performance against MQ armor and was generally superior to the mod.38 AP against armor of elevated hardness (either HHA or FHA).
III) 5cm Pzgr. 42, APCBC-HE
composite type (with welded on tip), with AP-cap and ballistic windscreen. Received improved heat treatment and fuze design. Introduced for 5cm FLAK-41 guns as anti-tank ammunition 1942/3. Same as late model 5cm Pzgr39 but with added windscreen for better downrange velocity.
Notice that when full calibre AP attacks armor, cast armor is only slightly inferior at 0° and considerably inferior to RHA at higher obliquities. This is because it cannot suffer from laminations like RHA (gas bubbles stay circular cavities in the cast matrix and doesn´t get cross rolled out to areas of latent lminations) but also doesn´t allow grain orientation to be employed protectively at oblique impact by aligning trajectory with the higher directional strain rate strength of a good RHA plate (a cross rolled out plate has elevated strain strength at longitudinal and latitudinal direction but not sectionwise, of course).