Guns penetration problem

[Alex1812]

Why the very close guns have absolutely different peteration values?

[Alex1812]

In one battle my M3A1 have destroyed 19 Pz.IVh and lossed only 12 own tanks. It looks like 37mm M6 is the super gun. Is it right?

[nedcorleone1]

Just because two guns have the same caliber (e.g. 37mm) does not mean that they should have equivalent penetration values. There are plenty of other significant components to this. Shell type, muzzle velocity, barrel length, manufacturing techniques, etc. The KwK36 has length of 46.5 calibers (or 172.05 cm) whereas the 37mm M6 gun has a length of 210cm. Shorter barrel usually equates to a lower velocity shell and shorter range, lowering a shell's effective penetration. Sure enough the KwK36 has a muzzle velocity of 726 m/s while the M6 has a muzzle velocity of 'up to 884 m/s'.


Furthermore, in response to your battle outcome, I am somewhat surprised to see the M3 Stuart performing so well against a PzIVh. The PzIVh should have 80mm frontal armor with 30mm at the sides and 20mm at the rear. Furthermore, the 'H' had 5mm side skirts effectively acting as spaced armor. A frontal shot from an M3 (with 76 mm of pen) would likely be ineffective at range unless the gunner was lucky enough to hit a weak point (i.e. vision slit, cupola, etc.). Of course we can dream of plenty of scenarios where the Shermans kept the PzIVh's pinned while the M3 outmaneuvered to the sides and rear for the killing shots which is certainly possible. Were the PzIVh's working in tandem? Did they have decent field coordination? Were they well supplied with rested crews? Maybe they got caught with their pants down and got spanked by the M3s. The M3s did close into a distance of 103 (feet?) and they got some good hits in.

[loki100]

I think Alex1812 is on to something

I've noticed in a number of detailed battle reports that my M3 Stuarts are the star of the show. So suspect a database issue?

[Alex1812]

Yes, detailed battle reports show that M3 Stuart and 37mm anti-tank gun are the best Allies equipments. It looks strange for me

[robinsa]

From what I can read in the document linked below this number seems to be fairly correct. I'm not sure why this is but it could be related to the munition used. Just comparing the caliber isn't very useful, just look at all the different 762 rounds out there! 762 Soviet is much "weaker" than the 762 Russian and NATO versions.


http://mr-home.staff.shef.ac.uk/hobbies/ww2pen3.pdf

[morvael]

The question is why the Stuarts were able to fire ten times per tank, whereas the Shermans only twice...

[robinsa]

Edit. Sorry thought the post above was in response to me. I realize now it's not.

[Smirfy]

It appears your IV's engaged targets with HE they Infact did rather well with HE, combined they were 120% effective whereas the Stuart's were only 54%.

The problem is the IV's did not prioritise and the Sherman's were a mere 8% effective.

The issue also appears to be range the 57mm AT gun is less effective than the 37mm AT gun because it fires at a longer range

[Smirfy]

I see your problem now you were defending with so little weapons 45 tanks and guns in total the American SPA even though only 39% effective (try getting that with the British) they destroyed damaged or disrupted 44% of the Germans .before they fired a shot. 68% of your force was out of action before the Stuart's fired.

[Smirfy]

When you look even closer air, has disputed 36 units so in reality before they fired a shot the force was 120% disrupted (whatever effect that has)

[Smirfy]

Fascinating battle the Germans have lost more tanks damaged and destroyed than they actually had

[nedcorleone1]

ORIGINAL: Smirfy

Fascinating battle the Germans have lost more tanks damaged and destroyed than they actually had

Honest question. How did you reach this conclusion?

[wokelly]

ORIGINAL: mr_flappypants

Just because two guns have the same caliber (e.g. 37mm) does not mean that they should have equivalent penetration values. There are plenty of other significant components to this. Shell type, muzzle velocity, barrel length, manufacturing techniques, etc. The KwK36 has length of 46.5 calibers (or 172.05 cm) whereas the 37mm M6 gun has a length of 210cm. Shorter barrel usually equates to a lower velocity shell and shorter range, lowering a shell's effective penetration. Sure enough the KwK36 has a muzzle velocity of 726 m/s while the M6 has a muzzle velocity of 'up to 884 m/s'.


Furthermore, in response to your battle outcome, I am somewhat surprised to see the M3 Stuart performing so well against a PzIVh. The PzIVh should have 80mm frontal armor with 30mm at the sides and 20mm at the rear. Furthermore, the 'H' had 5mm side skirts effectively acting as spaced armor. A frontal shot from an M3 (with 76 mm of pen) would likely be ineffective at range unless the gunner was lucky enough to hit a weak point (i.e. vision slit, cupola, etc.). Of course we can dream of plenty of scenarios where the Shermans kept the PzIVh's pinned while the M3 outmaneuvered to the sides and rear for the killing shots which is certainly possible. Were the PzIVh's working in tandem? Did they have decent field coordination? Were they well supplied with rested crews? Maybe they got caught with their pants down and got spanked by the M3s. The M3s did close into a distance of 103 (feet?) and they got some good hits in.

50mm Turret armor on the Mark IVG-J series tanks, completely vulnerable to 37mm fire from the front since the Stuart does something like 70mm penetration at 100 yards and this battle happened at 100 yards. A very small part of the overall tank (front hull) was safe from the 37mm at that range. Everywhere else it was very vulnerable.

[HMSWarspite]

ORIGINAL: mr_flappypants

Just because two guns have the same caliber (e.g. 37mm) does not mean that they should have equivalent penetration values. There are plenty of other significant components to this. Shell type, muzzle velocity, barrel length, manufacturing techniques, etc. The KwK36 has length of 46.5 calibers (or 172.05 cm) whereas the 37mm M6 gun has a length of 210cm. Shorter barrel usually equates to a lower velocity shell and shorter range, lowering a shell's effective penetration. Sure enough the KwK36 has a muzzle velocity of 726 m/s while the M6 has a muzzle velocity of 'up to 884 m/s'.

The KwK36 was nicknamed the door knocker. It was rather ineffective. The Allied equivalents were much better (US 37mm and UK 2pdr - 40mm calibre)

[nedcorleone1]

ORIGINAL: wokelly
50mm Turret armor on the Mark IVG-J series tanks, completely vulnerable to 37mm fire from the front since the Stuart does something like 70mm penetration at 100 yards and this battle happened at 100 yards. A very small part of the overall tank (front hull) was safe from the 37mm at that range. Everywhere else it was very vulnerable.

Ah yes, turret armor. I overlooked that piece. Don't the PzIVh models have the 8mm spaced armor as well on the turret (sides and rear)? 50mm + 8mm spaced would be more effective than 58mm of standard armor but not sure by how much. The idea is that a regular AP round hits the spaced armor and gets its trajectory deflected. The idea was that by deflecting the shot, the round would be hitting the actual armor of the tank at an angle, thereby increasing the effective armor thickness at the point of impact.

EDIT: I think that the original design of spaced armor on the PzIV series was to reduce the effectiveness of Russian anti-tank rifle rounds... not AP rounds.

[Smirfy]

ORIGINAL: mr_flappypants

ORIGINAL: Smirfy

Fascinating battle the Germans have lost more tanks damaged and destroyed than they actually had

Honest question. How did you reach this conclusion?

35 IVH
-26 destroyed
=9
-18 damaged
= -9

[morvael]

These are probably damaged first and destroyed second. Two damages equals destroy.

[Fishbed]

ORIGINAL: Alex1812

Why the very close guns have absolutely different peteration values?

I see that the PzIII still has a HVAP round with superior penetration value (94), do we know when special rounds may actually be used? Dice roll or systematic use when faced with "compatible" targets?

[wokelly]

ORIGINAL: mr_flappypants

ORIGINAL: wokelly
50mm Turret armor on the Mark IVG-J series tanks, completely vulnerable to 37mm fire from the front since the Stuart does something like 70mm penetration at 100 yards and this battle happened at 100 yards. A very small part of the overall tank (front hull) was safe from the 37mm at that range. Everywhere else it was very vulnerable.

Ah yes, turret armor. I overlooked that piece. Don't the PzIVh models have the 8mm spaced armor as well on the turret (sides and rear)? 50mm + 8mm spaced would be more effective than 58mm of standard armor but not sure by how much. The idea is that a regular AP round hits the spaced armor and gets its trajectory deflected. The idea was that by deflecting the shot, the round would be hitting the actual armor of the tank at an angle, thereby increasing the effective armor thickness at the point of impact.

EDIT: I think that the original design of spaced armor on the PzIV series was to reduce the effectiveness of Russian anti-tank rifle rounds... not AP rounds.

The 8mm armor (the side skirts right?), IIRC, was made of mild steel. It was purely to protect against Russian 14.5mm AT rifle rounds by essentially causing them to yaw after they passed through the skirts and hit the side armor at an angle that would not penetrate.

Its effectiveness against tank rounds would be non-existent, other then maybe stripping off the cap and ballistic cap on the round. Also, contrary to popular belief, the side skirts probably did not help against HEAT rounds as the distance between the skirts and the hull was not wide enough to cause the jet of molten to dissipate enough. This is why you don't see side skirts on Panther turrets and such despite being vulnerable to HEAT rounds on the flanks.