- Posts: 831
- Joined: 17 Apr 2002 10:44
- Location: Canada
Exactly! For the others,nose shattering was occured at overpenetration ratio 1,05 and over 2000 feet/sec due the GREATLY INCREASED nose stress (when the metal was pushing away faster) that did not bode well for the nose of M62 APCBC-HE-T despite of using armor piercing cap
The 75mm M61 APCBC-HE-T used by the M3 gun of the Sherman had much lower impact velocity (all under 2000 fps)values and the nose hardness was satisfactory,at least I don't know about any its opposite ,anybody else don't, too .
The 90mm M82 APCBC-HE-T-along with the 76mm-these are the best documented projectiles from world war era-nose damage was calculated minimal by all impact velocities
What more,solid-without inert he filler and cavity-,pointed nosed P projectiles without a ballistic cap (only with windscreen by the T33 and T43 90mm AP,AP for 105mm T8 gun) had better armor multipliers for sloped armor over 40 degree for some reason.Armor piercing-caps also absorbed impact energy and decreased penetration against homogenous armor but aid it against face-hardened.
The 90mm M3 L/52 gun with T33 AP with 2850 feet/sec muzzle velocity could pen the Panther glacis at longer range than the King Tiger with its own dreaded Kwk43 L/71 3280 feeet/sec despite its overpenetration (204mm vs 189mm against vertical armor WITHOUT side angle at 1000 meters)
Overall,the best impact characteristics against sloped armor had been owned by the russian blunt nosed APHE with a simple ballistic windscreen.[/quote]
Yes the US 75mm round had almost no shatter tendandcy due to its lower muzzle vel compared to the other US rounds you mentioned. On the other hand the CW 2, 6 and 17lb had some shatter tendency until later in the war at least. The CW ammo had no cavity for HE bursters and because of this should be more reistant to shatter than everyone else.
I suspect the verticle armour of many ger tanks esp tigers may have casued the shatter. If it had been sloped it might just bounce off but hitting a verticle slab of armour head on might cause the round to shatter. Even the ger FH arm which was not on the tigers would also cause rounds to shatter when hit.
On the other hand even the hard all the way through armour of the T34 which should be brittle might instead cause some rounds to shatter. Such the 88 early in the war.
The rus ammo was almost 20% less hard than the ger ammo almost double the allied numbers. Many of the rus guns that had vel over 2000' had bad reputation. The 45mm and 57mm gun to name two the latter of which had huge shatter tendencies. The 76 mm gun had muzzle vel simlilar to the US 75 and little shatter problems. It wasn´t until 44 that the rus started deploying guns and ammo such as the 85 and 122mm that had vel over 2000' and had less shatter tendency. They developed the special blunt nose projectile you mentioned which distrbuted the stress of the projectile over a larger area which should reduce shatter as well.
Yes the type of round and angle changes the solpe multipliers drasticallly in some cases. As well a lateral angle of 30 deg which the ger used could push the overall compound area from being good for one type of round to better for another. As well as make pen with any round impossible.
Some of the 90mm rounds towrds the end of the war were made as hard as the german rounds which should have reduced shatter.
- Posts: 149
- Joined: 29 Oct 2002 23:54
- Location: Nowhere
The front driver plate of the PzIIIH (32+30 FH armor plate bolted or layered together) resisted a combo like 57mm one-piece FH armor plate before calculating slope effects.
During british firing trials,the 75mm L/31 gin used by the Grant medium tank,PzIIIH driver plate was penetrated at 1500 meters and an exact side angle.
Though FH armor on PzIV G/H and PzIIIs worked well against 2 and 6pd AP,russian AP etc.