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  #21  
Old June 18th, 2011, 12:05 PM
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Default Re: British 75mm MkV tank gun

What I find interesting about the first source, is that they say:

It may be tempting to assume the performance of the British 75mm gun is the same as the USA 75mm Gun M3 as the two weapons used the same ammunition and had the same calibre; however it is a completely different gun and at the very least the difference in calibre length would mean a difference in muzzle velocity and therefore penetration.

But then they go on to give the Mark V a 2mm better penetration!



75mm Mark V and VA (L36.5)

APCBC M61 at 30deg (mv: 618 m/s)
457m : 68mm

75mm M3 and M6 (L40 and M6 L39)

APCBC M61 at 30deg (mv: 619 m/s)
457m : 66mm

914m: 60mm

AP M72 at 30deg (mv: 619 m/s)
457m : 76mm
914m: 63mm

Footnote:
1. Ordnance, QF, 75-mm Mk. V and Mk. VA. Source: Chamberlain, Peter and Ellis, Chris: British and American Tanks of World War II; Gudgin, Peter: Armoured Firepower and Churchill Tank - Vehicle History and Specification. This gun was a bored out 6-pounder chambered to use available 75mm ammunition from the USA. It may be tempting to assume the performance of the British 75mm gun is the same as the USA 75mm Gun M3 as the two weapons used the same ammunition and had the same calibre; however it is a completely different gun and at the very least the difference in calibre length would mean a difference in muzzle velocity and therefore penetration. None of the armour piercing projectiles had any explosive filler. The USA projectiles for the 75mm gun which were used by the British, such as the M61, had the HE filler removed when in British service.


http://www.friweb.hu/gva/weapons/british_guns5.html
http://www.friweb.hu/gva/weapons/usa_guns5.html
---

(All data is displayed in milimeters (mm) vs. RHA / FHA plate @ 30°)

75mm Mark V

APC M62 (mv: 618 m/s)
500: 67/65
1000: 52/49
1500: 40/37

75mm M3

APC M62 (mv: 588 m/s)
500: 64/75
1000: 57/68
1500: 51/61

APC M61 (mv: 617 m/s)
500: 69/67
1000: 61/58
1500: 53/49

AP M72 (mv: 619 m/s)
500: 73/58
1000: 59/45
1500: 47/34

http://www.tarrif.net/
---

75mm V and VA

yds
APC
500: 68
1000: 61
1500: 54

75mm M3

yds
APC
500: 70
1000: 59
1500: 55

75mm V and VA

yds
APCBC
500: 103
1000: 94
1500: 86

75mm M3

meters
APCBC
500: 75.3
1000: 62, 68.5
1500: 48, 55

75mm V and VA

meters
APCBC M61
500: 100
1000: 93
1500: 82

75mm M3

Meters
APCBC M61
500: 100
1000: 93
1500: 82

75mm V and VA

yds
AP M72
500: 76
1000: 63
1500: 51

yds
APC M61
500: 66
1000: 60
1500: 55

meters
APCBC
500: 69.5
1000: 63
1500: 57

75mm M3

Meters
APC M61
500: 70, 68
1000: 60, 59
1500: 55

Meters
AP
500: 76, 70
1000: 63
1500: 51

http://www.wwiivehicles.com/unitedki...ion-tables.asp
http://www.wwiivehicles.com/usa/guns/75-mm.asp

---

Bovington Museum, 1975
"Fire and Movement", RAC Tank Museum, Bovington, 1975, pages 22–25. "Penetration v. homogenous armour at 30º, at ranges in yards". The armour is machineable quality.

75mm Mk V

APC
500: 68
1000: 61
1500: 54

APCBC
500: 103
1000: 94
1500: 86

75mm M2 and M3

APC
500: 70
1000: 59
1500: 55

APCBC
500:
1000: 62
1500: 48

---

Chamberlain & Ellis, 1969
"British and American Tanks of World War II", Peter Chamberlain and Chris Ellis, A&AP, 1969, pages 202–207. Ranges in yards, armour type not specified, at 30º.

75mm Mk V, VA

500: 68

75mm M3

500: 70

75mm M2

500: 60


---

Ellis et al, 1962
"Victory in the West, Volume I: The Battle of Normandy", Maj. L F Ellis with Capt G R G Allen, Lt-Col A E Warhurst and ACM Sir James Robb, HMSO, 1962, page 549. "Penetration against homogenous armour plate at 30º angle of attack", ranges in yards.

75mm M3

APCBC
500: 74
1000: 68
1500: 60

perpetuates an error in Ellis by misidentifying the Sherman's 75mm gun as the British Mk V, when it is of course the US M3.

---

Ellis, 1993
"The World War II Databook", John Ellis, Aurum, 1993, page 304. Ranges in yards, armour type and slope not stated.

75mm M3

M61 APCBC
500: 66
1000: 61

---

Featherstone, 1973
"Tank Battles in Miniature: A wargamer's guide to the Western Desert Campaign 1940–1942", Donald Featherstone, Patrick Stevens Ltd, 1973, pages 141–143. "At 50º–90º angle-of-impact gun can penetrate maximum armour thickness of: (in millimetres)", ranges in yards, armour and ammunition types unspecified.

75mm M3

At 50 deg
600: 62
1000: 50

---

Gander & Chamberlain, 1977
Airfix Magazine guide 26, "American Tanks of World War 2", Terry Gander and Peter Chamberlain, Patrick Stevens Ltd, 1977.
Ranges in yards, ammunition type and armour type and slope unspecified.

75mm M3

500: 70

---


Grove, 1976
"World War II Tanks", Eric Grove, Orbis, 1976. Armour type unstated, conventional armour-piercing ammunition unless otherwise stated, ranges in yards.
At 30 deg

75mm M3

500: 70

---
Hunnicut, 1978
"Sherman, A History of the American Medium Tank", R. P. Hunnicutt, Presidio Press, 1978, pages 559–570. Ranges in yards; armour type (FH = Face-hardened, H = Homogenous) as shown at 30º.

75mm M3

APC (H)
500: 66
1000: 60
1500: 55

---

WO 185/178, Tank armament versus armour.
This file is dated 1943.
"Perforation of armour in millimetres":

75mm M3

AP M72 (MQ armour at 30deg)
500: 73
1000: 64
1500: 55

APCBC M61 (MQ armour at 30deg)
500: 76
1000: 69
1500: 58

APCBC M61 (FH armour at 30deg)
500: 75
1000: 67
1500: 52

"Thickness of armour penetrated by 80% of projectiles striking the plate at an angle of 30º to the normal":
(MV 2050 fps)

APCBC M61 (MQ armour at 30deg)
500: 69
1000: 62
1500: 47

APCBC M61 (FH armour at 30deg)
500: 74
1000: 65
1500: 50

A memo from the Ministry of Supply dated 1st April 1943 gives the following figures for "Single homo plate penetration at 30º in mm.":

A memo from the Ministry of Supply dated 1st April 1943 gives the following figures for "Single homo plate penetration at 30º in mm.":

APCBC (MV 2030 fps)
500: 69.5
1000: 63
1500: 57

---

WO 219/2806, Appendix G to SHAEF/16652/GCT/Arty
Dated 11 July 1944. "Perforation of homo at 30º Strike", ranges in yards.

US & Br 75mm

APCBC M61
600: 100
1000: 93
1600: 82

Comments and corrections
The high figures for the 75mm gun match those given for APCBC in the Bovington "Fire and Movement" booklet, but are much more generous than other sources. A memo in this document says there seems "little to choose" between the 75mm and 76mm.


---

WO 291/741, "Comparison of the performance of 75mm and 76mm tank gun ammunition."
"Thickness of homogenous armour plate penetrated at 30angle of attack by APCBC/HE shell." Ranges in yards.

75mm

APCBC
600: 68.5
1000: 63
1600: 55

Comments and corrections
Precision in fractional millimetres seems excessive, and suggests results by interpolation rather than measurement. This document also compares the HE performance of the two guns, concluding that in this respect the 75mm is noticeably superior. It also points out that inferior HE performance can be compensated for by using more of the less effective shell, whereas it is impossible to remedy a deficiency in penetrative performance.
---

Zaloga & Sarson, 1993
"Sherman Medium Tank 1942-1945", Steve Zaloga and Peter Sarson, Osprey 1993, pages 10 and 14. Armour type and slope unspecified, ranges in yards.

75mm M3

APC M61
500: 68
1000: 60

---

I took all the cited penetration and recorded them on a spreadsheet for the type of ammo they listed and ranges 500,1000,1500:



I put the averages at the bottom (in bold).

Then I changed the results from mm to cm (at the very bottom).

Of the 16 results I have for both weapons, 8 were same, 5 were higher for the Mark V, and 3 were higher for the M3.

Not the most scientific study, but based on the data that's available it shows that the weapons were considered quite similar.

In the game, it could be that the Mk V is a bit underpowered and the M3 a bit overpowered.


Cross
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  #22  
Old June 18th, 2011, 05:38 PM
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Default Re: British 75mm MkV tank gun

oops just noticed an error on my spreadsheet.

The averages for the Mark V, APC M61 ammo say:

500: 81
1000:63
1500:59

They should be:

500: 84
1000:82
1500:73

but once we get to cm it doesn;t effect the 500 range result, and only pushes up the 1000 and 1500 result by 1


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