So, I gathered up a bunch of data related to tank statistics and collected them at my website here LINK
Things that leap out from:
TM ORO-T-117, Survey of Allied Tank Casualties in World War II
http://alternatewars.com/BBOW/Ballistic ... es_WW2.pdf
are:
Ammunition Expenditure by Target Type:
AP Shot 34% (AFVs and Fortifications/Caves)
HE Shot 66% (Everything Else)
It's worth noting that the average tank target is 14.2%, rising to 24.4% in North Africa; whereas caves go from an average of 21.2% to 36.4% in the SWPA/PTO; so I would think that the rough figures (35 AP/65 HE) are a "it all comes out in the wash anyway" figure.
Engagement Ranges:
It appears that the average engagement range in WWII for tanks by the Western Allies was:
US ETO: 713.7 yards (690m) from 449 samples (from First, Third, Seventh and Ninth Armies)
UK ETO: 886.3 yards (810.4m) from 190 samples
UK Italy & Sicily: 324.05 yards (296.3m) from 57 samples
UK Africa: 890 yards (813m) from 96 samples
So use 800m for desert, 700m for Temperate, and 300m for Mountainous areas when calculating gun penetration figures; because computing on the outliers of Lt. Rose in a M36 Jackson scoring a 4600 yard (4200m) kill of a Panther...throws everything else out of wack:
https://www.ww2armor.org/blog-discussio ... -a-m36-gmc
Per Panzer War (LINK), at 700m (interpolating the data he gives) penetration is about this in millimeters (at 30 degrees):
37mm M3 with APC: 49~
75mm M3 with APC: 60~
76mm M1AC with APC: 90~
76mm M1AC with HVAP: 145~
90mm M3 with APC: 125~
90mm M3 with HVAP: 209~
You can weight further; most M4(76) only had about two HVAP rounds, out of 48 AP rounds total (roughly); so: (AP * 0.95) + (HVAP * 0.05)
76mm: 92.75
90mm: 129.2
If you do some extrapolation for TD units getting more HVAP:
(AP * 0.80) + (HVAP * 0.20)
76mm (TD): 101
90mm (TD): 149.8
Tank Hit Locations
349 hits were analyzed on US/UK/GER tanks in WWII, and they shake out roughly as:
Turret hits were broken down as:
31% Front
64% Side
4% Rear
Hull hits were broken down as:
29% Front
65% Side
6% Rear
So a good reasonable approximation of protected surface being hit is:
30% Frontal
65% Side
5% Rear
As for the turret/hull hit percentages...
35% hit the Turret
65% hit the Hull
Calculating a Simplified Armor Score
Turret General Rating = (FrontArmor * 0.30) + (SideArmor * 0.65) + (RearArmor * 0.05)
Hull General Rating = (FrontArmor * 0.30) + (SideArmor * 0.65) + (RearArmor * 0.05)
Tank General Rating = (TurretGeneralRating * 0.35) + (HullGeneralRating * 0.65)
This results in armor numbers being:
Panzer IVH: 48.2
Panther A: 79.1
Tiger I: 96.7
Tiger II: 131
M4A3 76(W): 59.9
M26: 95.6
T-34/85: 74.9
IS-2: 114.8
IS-3: 183.4
BONUS:
T-54-1: 138.7
It's easy to see how the T-54/55 series basically took over post-war; beating out the other IS series tanks.
EDIT: And I know you're going to ask; what's with the T-54 and IS-3?
It's because they have very thick side armor, especially on turrets; as they were the first tanks to use the "inverted frying pan" type of scheme common in post-war soviet tanks.
Because we're weighting side armor (65% of hits vs only 30% frontal), it means the traditional armor values given "OMG Panther has 140mm equivalent frontal armor!" don't count as much, because if your tank has weak side armor (hello Mr. Panther), it gets penalized.
The Deadliest Tank
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MKSheppard
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- Joined: Mon Nov 21, 2022 1:41 am
The Deadliest Tank
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MKSheppard
- Posts: 438
- Joined: Mon Nov 21, 2022 1:41 am
Re: The Deadliest Tank
We normalize main gun "soft" firepower against the Mark II Grenade used by the US from 1919 to 1969.
The Mk II Grenade weighed 600 grams and had a 52 gram TNT filling.
So a rough SOFT firepower formula is 1 point of HE firepower for every 0.05 kilograms of HE filler, with some adjustments goes...
SOFT FIREPOWER = (FillingMass / 0.05) * ROF * (MVel / 600)
where:
FillingMass = Mass of HE filler in kilograms.
ROF = Rate of fire in rounds per minute
MVel = Muzzle Velocity in m/sec.
With this formula, we get:
The 75mm M3 gun with the M48 HE round had a 6.76 kg proj mass, with 0.68 kg HE @ 625 m/s. Assuming 12 rounds a minute; we get a 170 HE score.
The 76mm M1 gun with the M42A1 HE round had a 5.84 kg proj mass, with 0.39 kg HE @ 820 m/s. Assuming 12 rounds a minute; we get a 127.92 HE score.
The 90mm M3 Gun with the M71 HE round had a 10.56 kg proj mass, with 0.975 kg HE @ 822 m/s. Assuming 8 rounds a minute; we get a 213.72 HE score.
The 105mm M4 Howitzer with the M1 HE round had 14.97 kg proj mass, with 2.18 kg HE @ 472 m/s. Assuming 6 rounds a minute (assumption fair for something with no power turret traverse); we get a 205.7 HE score.
The 7.5 cm KWK 37 L/24 with the 7.5cm SpGr. 34 round had a 4.42 kg proj mass, with 0.454 kg of HE @ 420 m/s. Assuming 12 rounds a minute; we get a 76.2 HE score.
The 7.5 cm KWK 42 L/70 with the 7.5cm SpGr. 42 round had a 5.74 kg proj mass, with 0.65 kg of HE @ 700 m/s. Assuming 6 rounds a minute; we get a 91 HE score.
There's some more stuff I need to figure out; like rangefinder multipliers -- the StuG had the early 7.5 cm L/24, with low muzzle velocity = inaccurate, but it also had specialist binocular rangefinders and other equipment, making it's shots more accurate.
The Mk II Grenade weighed 600 grams and had a 52 gram TNT filling.
So a rough SOFT firepower formula is 1 point of HE firepower for every 0.05 kilograms of HE filler, with some adjustments goes...
SOFT FIREPOWER = (FillingMass / 0.05) * ROF * (MVel / 600)
where:
FillingMass = Mass of HE filler in kilograms.
ROF = Rate of fire in rounds per minute
MVel = Muzzle Velocity in m/sec.
With this formula, we get:
The 75mm M3 gun with the M48 HE round had a 6.76 kg proj mass, with 0.68 kg HE @ 625 m/s. Assuming 12 rounds a minute; we get a 170 HE score.
The 76mm M1 gun with the M42A1 HE round had a 5.84 kg proj mass, with 0.39 kg HE @ 820 m/s. Assuming 12 rounds a minute; we get a 127.92 HE score.
The 90mm M3 Gun with the M71 HE round had a 10.56 kg proj mass, with 0.975 kg HE @ 822 m/s. Assuming 8 rounds a minute; we get a 213.72 HE score.
The 105mm M4 Howitzer with the M1 HE round had 14.97 kg proj mass, with 2.18 kg HE @ 472 m/s. Assuming 6 rounds a minute (assumption fair for something with no power turret traverse); we get a 205.7 HE score.
The 7.5 cm KWK 37 L/24 with the 7.5cm SpGr. 34 round had a 4.42 kg proj mass, with 0.454 kg of HE @ 420 m/s. Assuming 12 rounds a minute; we get a 76.2 HE score.
The 7.5 cm KWK 42 L/70 with the 7.5cm SpGr. 42 round had a 5.74 kg proj mass, with 0.65 kg of HE @ 700 m/s. Assuming 6 rounds a minute; we get a 91 HE score.
There's some more stuff I need to figure out; like rangefinder multipliers -- the StuG had the early 7.5 cm L/24, with low muzzle velocity = inaccurate, but it also had specialist binocular rangefinders and other equipment, making it's shots more accurate.
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MKSheppard
- Posts: 438
- Joined: Mon Nov 21, 2022 1:41 am
Re: The Deadliest Tank
Firepower, Revision 2.0
We normalize main gun "soft" firepower against the Mark II Grenade used by the US from 1919 to 1969.
The Mk II Grenade weighed 600 grams and had a 52 gram TNT filling.
So a rough SOFT firepower formula is 1 point of HE firepower for every 0.05 kilograms of HE filler, with some adjustments goes...
SOFT FIREPOWER = (FillingMass / 0.05) * ROF * (PHit * 10)
Where:
FillingMass = Mass of HE filler in kilograms.
ROF = Rate of fire in rounds per minute; capped at 12 RPM; representing the fact that while theoretically, the M4 had a 20 RPM ROF, the gunner/commander still needed time to acquire, fire, and reacquire the target and do BDA; a 5 second OODA loop (60 seconds / 12 = 5) provides this.
Tanks did a lot more with their time than World Of Tanks / War Thunder Fury-esque split second duels; and the ROF here represents this.
For automatic weapons such as the 25mm M242 Chaingun, which can fire 200 RPM in high rate; the ROF calculation is: (Rounds Per Second * 12), representing twelve one-second bursts by the gunner as part of a "OODA" acquistion/fire loop.
PHit = Probability of first round hit.
The PHit calculation is [ -0.03315 + (0.00019 * MVel) ]
NOTE: I based this off first round probability hit data I found here
https://www.quora.com/How-accurate-were ... -cm-KwK-42
and converted it into a linear formula.
MVel = Muzzle Velocity in m/sec.
There's a lot of stuff we could try to find, such as gun dispersion -- the US 76mm M1 gun was the most accurate gun regarding dispersion that the British tested at one time in WW2; but it's not likely that we'll find accurate dispersion values for every tank out there. So muzzle velocity is a good "stand-in" for overall accuracy, given rangefinding in WW2.
With this refined formula, we get:
==========================
US guns:
==========================
The 37mm M6 gun with the M63 HE round had a 0.73 kg proj mass, with 0.039 kg HE @ 792 m/s. Assuming 12 rounds a minute; we get a 11.0 HE score.
The 57mm (6-Pdr) gun with the Mk 10T HE round had a 2.72 kg proj mass, with 0.272 kg HE @ 822 m/s. Assuming 12 rounds a minute; we get a 80.3 HE score. [estimate based off having 40% of the charge of the 75mm M3 given in "Tiger vs Churchill: North-West Europe, 1944–45"]
The 75mm M3 gun with the M48 HE round had a 6.76 kg proj mass, with 0.68 kg HE @ 625 m/s. Assuming 12 rounds a minute; we get a 139.7 HE score.
The 76mm M1 gun with the M42A1 HE round had a 5.84 kg proj mass, with 0.39 kg HE @ 820 m/s. Assuming 12 rounds a minute; we get a 114.8 HE score.
The 90mm M3 Gun with the M71 HE round had a 10.56 kg proj mass, with 0.975 kg HE @ 822 m/s. Assuming 8 rounds a minute; we get a 191.9 HE score.
The 105mm M4 Howitzer with the M1 HE round had 14.97 kg proj mass, with 2.18 kg HE @ 472 m/s. Assuming 8 rounds a minute; we get a 197.2 HE score.
==========================
German Guns
==========================
The 7.5 cm KWK 37 L/24 with the 7.5cm SpGr. 34 round had a 4.42 kg proj mass, with 0.454 kg of HE @ 420 m/s. Assuming 12 rounds a minute; we get a 50.8 HE score.
The 7.5 cm KWK 40 L/48 with the 7.5cm Sprgr.Patr.34 round had a 5.75 kg proj mass, with 0.66 kg of HE @ 550 m/s. Assuming 12 rounds a minute; we get a 113.0 HE score.
The 7.5 cm KWK 42 L/70 with the 7.5cm SpGr. 42 round had a 5.74 kg proj mass, with 0.65 kg of HE @ 700 m/s. Assuming 10 rounds a minute; we get a 129.8 HE score.
The 8.8 cm KWK 36 L/56 with the 8.8cm Sprgr. round had a 9.3 kg proj mass, with 0.9 kg of HE @ 820 m/s. Assuming 8 rounds a minute; we get a 176.6 HE score.
The 8.8 cm KWK 43 L/71 with the 8.8cm Sprgr. 43 round had a 9.5 kg proj mass, with 1.02 kg of HE @ 750 m/s. Assuming 6 rounds a minute; we get a 133.8 HE score.
[
SEE:
http://www.tankarchives.ca/2016/01/germ ... rates.html
https://archive.org/details/WO2911003Mo ... ermanTanks
]
==========================
TANK MACHINE GUNS.
To calculate the casualty radius of small arms, of which a machine gun is; we return once again to that good old standby, the Mk II Grenade, which had a "casualty radius" of about 10 meters (314.16 m2); or a projected area of 20 x 1.5 = 30m2.
We estimate a machine gun by the following equation:
RPM = (RPS * 3 * 12) = Rounds Fired in One Minute (3-second bursts, 12 bursts in total). Unlike big tank guns, machine guns have very little smoke/dust and you can walk the tracers onto target, plus 150-200 round canvas belts give you room for spraying ammo.
RawFirepower = RPM / (30 * 1.25) -- we multiply the projected area of 30m2 by 1.25 for a "margin of error" to catch people kneeling, etc. Or you can just divide RPM by 37.5 and be done with it.
ScaledFirepower = RawFirepower * (MassGrams / 11)^0.45
This scales firepower to a rough average of a .30-06 and 7.92mm bullet mass; because machine guns (usually) were non-explosive; with the exponent function preventing HMGs such as the 12.7mm M2HB or 14.5mm KPV from becoming grossly overpowering due to sheer bullet mass.
With this number, we get:
M1919 (10 RPS): 9.6
MG34 (13.33 RPS): 12.8
MG42 (20 RPS): 19.2
M2HB (8.75 RPS): 15.5
KPV (10 RPS): 21.3
The numbers might be high; but you can see how and why there was a mania for machine gun only tankettes/light tanks in the 1920s and early 1930s -- the firepower level (9 to 10) is about the same as a 37mm gun and you can put a lot more machine guns onto a tank as they don't need recoil systems and you can place a lot of stowed kills onboard.
We normalize main gun "soft" firepower against the Mark II Grenade used by the US from 1919 to 1969.
The Mk II Grenade weighed 600 grams and had a 52 gram TNT filling.
So a rough SOFT firepower formula is 1 point of HE firepower for every 0.05 kilograms of HE filler, with some adjustments goes...
SOFT FIREPOWER = (FillingMass / 0.05) * ROF * (PHit * 10)
Where:
FillingMass = Mass of HE filler in kilograms.
ROF = Rate of fire in rounds per minute; capped at 12 RPM; representing the fact that while theoretically, the M4 had a 20 RPM ROF, the gunner/commander still needed time to acquire, fire, and reacquire the target and do BDA; a 5 second OODA loop (60 seconds / 12 = 5) provides this.
Tanks did a lot more with their time than World Of Tanks / War Thunder Fury-esque split second duels; and the ROF here represents this.
For automatic weapons such as the 25mm M242 Chaingun, which can fire 200 RPM in high rate; the ROF calculation is: (Rounds Per Second * 12), representing twelve one-second bursts by the gunner as part of a "OODA" acquistion/fire loop.
PHit = Probability of first round hit.
The PHit calculation is [ -0.03315 + (0.00019 * MVel) ]
NOTE: I based this off first round probability hit data I found here
https://www.quora.com/How-accurate-were ... -cm-KwK-42
and converted it into a linear formula.
MVel = Muzzle Velocity in m/sec.
There's a lot of stuff we could try to find, such as gun dispersion -- the US 76mm M1 gun was the most accurate gun regarding dispersion that the British tested at one time in WW2; but it's not likely that we'll find accurate dispersion values for every tank out there. So muzzle velocity is a good "stand-in" for overall accuracy, given rangefinding in WW2.
With this refined formula, we get:
==========================
US guns:
==========================
The 37mm M6 gun with the M63 HE round had a 0.73 kg proj mass, with 0.039 kg HE @ 792 m/s. Assuming 12 rounds a minute; we get a 11.0 HE score.
The 57mm (6-Pdr) gun with the Mk 10T HE round had a 2.72 kg proj mass, with 0.272 kg HE @ 822 m/s. Assuming 12 rounds a minute; we get a 80.3 HE score. [estimate based off having 40% of the charge of the 75mm M3 given in "Tiger vs Churchill: North-West Europe, 1944–45"]
The 75mm M3 gun with the M48 HE round had a 6.76 kg proj mass, with 0.68 kg HE @ 625 m/s. Assuming 12 rounds a minute; we get a 139.7 HE score.
The 76mm M1 gun with the M42A1 HE round had a 5.84 kg proj mass, with 0.39 kg HE @ 820 m/s. Assuming 12 rounds a minute; we get a 114.8 HE score.
The 90mm M3 Gun with the M71 HE round had a 10.56 kg proj mass, with 0.975 kg HE @ 822 m/s. Assuming 8 rounds a minute; we get a 191.9 HE score.
The 105mm M4 Howitzer with the M1 HE round had 14.97 kg proj mass, with 2.18 kg HE @ 472 m/s. Assuming 8 rounds a minute; we get a 197.2 HE score.
==========================
German Guns
==========================
The 7.5 cm KWK 37 L/24 with the 7.5cm SpGr. 34 round had a 4.42 kg proj mass, with 0.454 kg of HE @ 420 m/s. Assuming 12 rounds a minute; we get a 50.8 HE score.
The 7.5 cm KWK 40 L/48 with the 7.5cm Sprgr.Patr.34 round had a 5.75 kg proj mass, with 0.66 kg of HE @ 550 m/s. Assuming 12 rounds a minute; we get a 113.0 HE score.
The 7.5 cm KWK 42 L/70 with the 7.5cm SpGr. 42 round had a 5.74 kg proj mass, with 0.65 kg of HE @ 700 m/s. Assuming 10 rounds a minute; we get a 129.8 HE score.
The 8.8 cm KWK 36 L/56 with the 8.8cm Sprgr. round had a 9.3 kg proj mass, with 0.9 kg of HE @ 820 m/s. Assuming 8 rounds a minute; we get a 176.6 HE score.
The 8.8 cm KWK 43 L/71 with the 8.8cm Sprgr. 43 round had a 9.5 kg proj mass, with 1.02 kg of HE @ 750 m/s. Assuming 6 rounds a minute; we get a 133.8 HE score.
[
SEE:
http://www.tankarchives.ca/2016/01/germ ... rates.html
https://archive.org/details/WO2911003Mo ... ermanTanks
]
==========================
TANK MACHINE GUNS.
To calculate the casualty radius of small arms, of which a machine gun is; we return once again to that good old standby, the Mk II Grenade, which had a "casualty radius" of about 10 meters (314.16 m2); or a projected area of 20 x 1.5 = 30m2.
We estimate a machine gun by the following equation:
RPM = (RPS * 3 * 12) = Rounds Fired in One Minute (3-second bursts, 12 bursts in total). Unlike big tank guns, machine guns have very little smoke/dust and you can walk the tracers onto target, plus 150-200 round canvas belts give you room for spraying ammo.
RawFirepower = RPM / (30 * 1.25) -- we multiply the projected area of 30m2 by 1.25 for a "margin of error" to catch people kneeling, etc. Or you can just divide RPM by 37.5 and be done with it.
ScaledFirepower = RawFirepower * (MassGrams / 11)^0.45
This scales firepower to a rough average of a .30-06 and 7.92mm bullet mass; because machine guns (usually) were non-explosive; with the exponent function preventing HMGs such as the 12.7mm M2HB or 14.5mm KPV from becoming grossly overpowering due to sheer bullet mass.
With this number, we get:
M1919 (10 RPS): 9.6
MG34 (13.33 RPS): 12.8
MG42 (20 RPS): 19.2
M2HB (8.75 RPS): 15.5
KPV (10 RPS): 21.3
The numbers might be high; but you can see how and why there was a mania for machine gun only tankettes/light tanks in the 1920s and early 1930s -- the firepower level (9 to 10) is about the same as a 37mm gun and you can put a lot more machine guns onto a tank as they don't need recoil systems and you can place a lot of stowed kills onboard.
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Nik_SpeakerToCats
- Posts: 1740
- Joined: Sat Dec 10, 2022 10:56 am
Re: The Deadliest Tank
Beyond the 'in combat' performance, could you factor in ammunition storage, fuel/range and repair/maintenance ??
Examples being the remarkable 'King Tiger' which, in right hands, made a tank-kill with each shot, but had to 'disengage' as out of AP and bingo on fuel.
Also, such as overlapping road-wheels, which gave an excellent ride, but were loathed by mechanics as you had to take several 'front' wheels off to access any 'behind'...
Also, such 'oopsies' as otherwise excellent UK tanks with engines that were almost unserviceable 'in the field' due pi$$-poor access provision...
Examples being the remarkable 'King Tiger' which, in right hands, made a tank-kill with each shot, but had to 'disengage' as out of AP and bingo on fuel.
Also, such as overlapping road-wheels, which gave an excellent ride, but were loathed by mechanics as you had to take several 'front' wheels off to access any 'behind'...
Also, such 'oopsies' as otherwise excellent UK tanks with engines that were almost unserviceable 'in the field' due pi$$-poor access provision...
If you cannot see the wood for the trees, deploy LIDAR.
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MKSheppard
- Posts: 438
- Joined: Mon Nov 21, 2022 1:41 am
Re: The Deadliest Tank
Stowed kills are going to be big. That was one reason why the M26 Pershing (and other tanks) were so delayed to reach ETO.Nik_SpeakerToCats wrote: ↑Sat Dec 10, 2022 12:42 pm Beyond the 'in combat' performance, could you factor in ammunition storage, fuel/range and repair/maintenance ??
See; Eisenhower's HQ kept saying WE WILL NOT ACCEPT ANY TANK WITH LESS THAN SEVENTY ROUNDS of main gun ammo.
Ammunition. Seventy (70) rounds of ammunition is the minimum acceptable in each tank, with both types of weapon. Seventy (70) rounds is to be considered as the minimum figure -- more rounds are urgently desired.
T25:
It will not meet the theater's stated requirement for ammunition. Extreme difficulty is being encountered in providing an accessible stowage of fifty-two (52) rounds of ammunition.
...
The most difficult requirement to meet in using this tank is the requirement for 70 rounds. It is estimated that a maximum of 52 rounds can be installed in the present tank. By eliminating the bow machine gun and bow machine gunner and using this space for ammunition, it is estimated that an additional 18 rounds could be stowed. This ammunition would be without water protection.
The T26 had the same problem.
I'm still not quite sure how to work out reliability/cruising radius -- as a lot of that is not easily available.Examples being the remarkable 'King Tiger' which, in right hands, made a tank-kill with each shot, but had to 'disengage' as out of AP and bingo on fuel.
Also, such as overlapping road-wheels, which gave an excellent ride, but were loathed by mechanics as you had to take several 'front' wheels off to access any 'behind'...
Also, such 'oopsies' as otherwise excellent UK tanks with engines that were almost unserviceable 'in the field' due pi$$-poor access provision...
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MKSheppard
- Posts: 438
- Joined: Mon Nov 21, 2022 1:41 am
Re: The Deadliest Tank
Fastest Gun in the (Western) Desert
Muzzle velocity is weighted into the score; because it's the only good "clear" metric we have on gun accuracy for first round hits; without getting detailed gun dispersion reports; which won't be available for every gun.
All the guns here are small enough that they don't sink below the 12 RPM cap (that's a 5 round OODA cycle).
NOTE: I deliberately capped guns at 12 RPM, because we're looking for semi-aimed gunfire here, not "mad minute" LOAD LOAD TIGER TIGER LOAD LOAD LOAD; since tanks spent 85% of their time slinging HE at stuff other than enemy tanks. You need to be able to fire, recover from dust kicked up, observe the shot hit the target and adjust fire.
Also; do you think this guy is getting effective rounds on target? (https://twitter.com/AFVphotos/status/16 ... 6567230465)
Without further ado, here we are (HE numbers were scaled off the US Mk II Grenade btw)
Allied Guns
2-pounder (1.575" / 40mm): HE/T Mk II Shot (0.86 kg with 0.085 kg of HE) @ 792 m/s;
At 12 RPM, we get 23.9 HE Score.
6-pounder (2.244" / 57mm): HE Mk 10T Shot (1.25~ kg with 0.27 kg of HE) @ 820 m/s.
At 12 RPM, we get 79.5 HE Score.
75mm M3: M48 HE (6.76 kg with 0.675 kg HE) @ 625 m/s.
At 12 RPM, we get 138.7 HE Score.
German Guns
3.7 cm KwK 36 L/45: Sprenggranate 40 (0.664 kg with 0.045 kg HE) @ 680 m/s.
At 12 RPM, we get 10.4 HE Score.
5cm KwK 38: Sprenggranate 38 (1.82 kg with 0.170 kg HE) @ 450 m/s.
At 12 RPM, we get 21.4 HE Score.
7.5cm KwK 37 L/24: Sprenggranate 34 (4.42 kg with 0.454 kg HE) @ 420 m/s.
At 12 RPM, we get 50.8 HE Score.
7.5 cm KWK 40 L/48: Sprenggranate 34 (5.75 kg with 0.66 kg HE) @ 550 m/s.
At 12 RPM, we get 113.0 HE Score.
==============
What's interesting here is that German guns throughout WWII were handicapped by their low muzzle velocity relative to other HE flingers -- the US 75mm M3 gun has a rather high HE muzzle velocity of 625 m/s; and the 76mm M1 had an even higher 820 m/s.
NOTE: as an aside, when the UK tested tank guns, they found that the 76mm M1 had the lowest dispersion of tank guns they tested; which explains why the Pacific Theater wanted as many 76mm armed tanks as possible for DOWNFALL because it took significantly less rounds (both HE and AP) to hit/destroy bunkers than the 75mm gun.
Muzzle velocity is weighted into the score; because it's the only good "clear" metric we have on gun accuracy for first round hits; without getting detailed gun dispersion reports; which won't be available for every gun.
All the guns here are small enough that they don't sink below the 12 RPM cap (that's a 5 round OODA cycle).
NOTE: I deliberately capped guns at 12 RPM, because we're looking for semi-aimed gunfire here, not "mad minute" LOAD LOAD TIGER TIGER LOAD LOAD LOAD; since tanks spent 85% of their time slinging HE at stuff other than enemy tanks. You need to be able to fire, recover from dust kicked up, observe the shot hit the target and adjust fire.
Also; do you think this guy is getting effective rounds on target? (https://twitter.com/AFVphotos/status/16 ... 6567230465)
Without further ado, here we are (HE numbers were scaled off the US Mk II Grenade btw)
Allied Guns
2-pounder (1.575" / 40mm): HE/T Mk II Shot (0.86 kg with 0.085 kg of HE) @ 792 m/s;
At 12 RPM, we get 23.9 HE Score.
6-pounder (2.244" / 57mm): HE Mk 10T Shot (1.25~ kg with 0.27 kg of HE) @ 820 m/s.
At 12 RPM, we get 79.5 HE Score.
75mm M3: M48 HE (6.76 kg with 0.675 kg HE) @ 625 m/s.
At 12 RPM, we get 138.7 HE Score.
German Guns
3.7 cm KwK 36 L/45: Sprenggranate 40 (0.664 kg with 0.045 kg HE) @ 680 m/s.
At 12 RPM, we get 10.4 HE Score.
5cm KwK 38: Sprenggranate 38 (1.82 kg with 0.170 kg HE) @ 450 m/s.
At 12 RPM, we get 21.4 HE Score.
7.5cm KwK 37 L/24: Sprenggranate 34 (4.42 kg with 0.454 kg HE) @ 420 m/s.
At 12 RPM, we get 50.8 HE Score.
7.5 cm KWK 40 L/48: Sprenggranate 34 (5.75 kg with 0.66 kg HE) @ 550 m/s.
At 12 RPM, we get 113.0 HE Score.
==============
What's interesting here is that German guns throughout WWII were handicapped by their low muzzle velocity relative to other HE flingers -- the US 75mm M3 gun has a rather high HE muzzle velocity of 625 m/s; and the 76mm M1 had an even higher 820 m/s.
NOTE: as an aside, when the UK tested tank guns, they found that the 76mm M1 had the lowest dispersion of tank guns they tested; which explains why the Pacific Theater wanted as many 76mm armed tanks as possible for DOWNFALL because it took significantly less rounds (both HE and AP) to hit/destroy bunkers than the 75mm gun.
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Nik_SpeakerToCats
- Posts: 1740
- Joined: Sat Dec 10, 2022 10:56 am
Clarification: that 75 vs 76
Was it just the muzzle velocity that let the 76 be more accurate than the 75 ??
Or was that combined with better mount, range-finding, traverse etc...
I'm reminded that one of the UK's 'best' war-time tank up-gun prototypes had such a lonnnng recoil that it was not accepted. Excellent gun, but adapted from 'Towed Artillery' that lacked length constraints. Getting it into turret by adding what we'd call a bustle was the last straw, due to the increased weight of turret slowing both tank and traverse.
IIRC, a rival gun with a much shorter recoil got the nod for tanks, and the other fetched up in lighter-armoured 'tank destroyers'...
Or was that combined with better mount, range-finding, traverse etc...
I'm reminded that one of the UK's 'best' war-time tank up-gun prototypes had such a lonnnng recoil that it was not accepted. Excellent gun, but adapted from 'Towed Artillery' that lacked length constraints. Getting it into turret by adding what we'd call a bustle was the last straw, due to the increased weight of turret slowing both tank and traverse.
IIRC, a rival gun with a much shorter recoil got the nod for tanks, and the other fetched up in lighter-armoured 'tank destroyers'...
If you cannot see the wood for the trees, deploy LIDAR.
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MKSheppard
- Posts: 438
- Joined: Mon Nov 21, 2022 1:41 am
Re: Clarification: that 75 vs 76
Apparently the 76mm had really low dispersion; but that runs into a big problem that Stuart and others found with the Deadliest Air Warrior work:Nik_SpeakerToCats wrote: ↑Tue Dec 27, 2022 6:43 pm Was it just the muzzle velocity that let the 76 be more accurate than the 75 ??
Even if we do manage to get the data for these two aircraft (F4U vs F6F accident rates), we then have to get the same data for every other aircraft in the world. It's just not possible.
Dispersion data is different for every type of round fired; and it's extremely obscure -- obscure enough that there's no way we can get it for random tank from WWII...