WW II Ballistics Tank Gun Penetration - UK

The following is my choice of British gun penetration data.  Penetration criteria in this case is 'The Thickness against Critical Velocity for Perforation'.  This criteria is based on a 50% probability of a successful penetration. A successful penetration is at least 20% of the mass passing 'as a free missile' through the armor.  The US and British 50% criteria are statistically the same. Tests of British guns produced firing graphs.  Firing tables were made from these graphs and distributed to various boards.

Tank and Anti-tank Guns
Penetration figures use American and British 50% success criteria.
Gun TypeAmmunitionAngleMuzzle velocity Penetration (mm)
0 yd250 yd500 yd1000 yd1250 yd1500 yd2000 yd2500 yd
OQF 2 pdr.AP 130 2600 ft/s ( 792 m/s) 66 59 52 40 35 30 24
OQF 2 pdr.AP 1 0 2600 ft/s ( 792 m/s) 90 78 67 48 41 35 26
OQF 2 pdr.APHV 130 2800 ft/s ( 853 m/s) 72 64 57 44 39 33 25
OQF 2 pdr.APHV 1 0 2800 ft/s ( 853 m/s) 100 86 75 54 46 39 29
OQF 2 pdr.APCBC 230 2600 ft/s ( 792 m/s) 63 60 56 49 43 38 32
OQF 2 pdr.Littlejohn Mk I 1030 4200 ft/s (1280 m/s) 115 99 86 63 53 45
OQF 2 pdr.Littlejohn Mk II 1130 3750 ft/s (1143 m/s) 103 96 89 76 70 64 54
OQF 6 pdr.AP 330 2800 ft/s ( 853 m/s) 100 84 70 57 45
OQF 6 pdr.AP 330 2925 ft/s ( 892 m/s) 104 88 73 60 48
OQF 6 pdr.APC 430 2775 ft/s ( 846 m/s) 94 77 64 49 38
OQF 6 pdr.APC 430 2900 ft/s ( 884 m/s) 100 82 66 53 43
OQF 6 pdr.APCBC 530 2600 ft/s ( 792 m/s) 89 82 75 68 62
OQF 6 pdr.APCBC 530 2725 ft/s ( 831 m/s) 95 87 80 73 67
OQF 6 pdr.Sabot 1230 4000 ft/s (1219 m/s) 151 134118 103 90
OQF 17 pdrAPC 630 2600 ft/s ( 792 m/s) 126 115103 91 81
OQF 77mmAPCBC 930 2575 ft/s ( 785 m/s) 128 118110 100 93
OQF 77mmSabot 12 30 3675 ft/s (1120 m/s) 182 165149 134120
OQF 17 pdrAP 730 2900 ft/s ( 884 m/s) 132 120109 98 91 87
OQF 17 pdrAPC 630 2900 ft/s ( 884 m/s) 132 120109 98 87
OQF 17 pdrAPCBC 830 2900 ft/s ( 884 m/s) 132129126120117114107
OQF 17 pdrAPCBC 9 0 2900 ft/s ( 884 m/s) 162 139
OQF 17 pdrAPCBC 930 2900 ft/s ( 884 m/s) 152 140130 120112
OQF 17 pdrSabot 1230 3680 ft/s (1122 m/s) 201 186172 158145

Citations
1.  British Ordnance Board 1944 Ordnance Quick Fire 2 pdr. A.P. shot graph OB/44/CV 28
2.  British Ordnance Board 1943  Ordnance Quick Fire 2 pdr. A.P.C.B.C. graph OB/43/CV 4
3.  British Ordnance Board 2/1/1944 Ordnance Quick Fire  6 pdr. A.P. graph OB/44/CV 25
4.  British Ordnance Board 3/19/1943 Ordnance Quick Fire  6 pdr. A.P.C. graph OB/43/CV 2
5.  British Ordnance Board 5/18/1944 Ordnance Quick Fire  6 pdr. A.P.C.B.C. graph OB/44/CV 38
6.  British Ordnance Board 1943 Ordnance Quick Fire  17 pdr. A.P.C. graph OB/44/CV 7
7.  British Ordnance Board 1943 Ordnance Quick Fire  17 pdr. A.P. graph OB/44/CV 10
8.  British Ordnance Board Ordnance Quick Fire 17 pdr Est. Proc. No. 22834
9.  British Ordnance Board 1944 Ordnance Quick Fire  77mm. & 17 pdr A.P.C.B.C graph OB/CV 44
10.  British Ordnance Board 1944 Ordnance Quick Fire 2 pr. Littlejohn Mk I graph OB/44/CV 40
11.  British Ordnance Board 1944 Ordnance Quick Fire 2 pr. Littlejohn Mk II graph OB/44/CV 41
12. CSAR core graph

Critical Velocity graphs.
17 pdr APCBC
17 pdr APC
17 pdr AP
2 pdr projectiles
2 pdt AP
2 pdr projectiles
6 pdr projectiles

Armor Basis is Averaged and Normalized to RHA BHN 270
Penetration figures use 50% success criteria.
Gun TypeAmmunitionAngleMuzzle velocity Penetration (mm)
100 m300 m500 m1000 m1500 m2000 m2500 m3000 m
OQF 40mm BoforsAP* 0 2650 m/s (8694 ft/s) 82 79 74 59 47 38 28 19
OQF 2 pdrAPHE 0 2600 m/s (8530 ft/s) 56 53 51 41 30 23 13 7
OQF 2 pdrAP 0 2600 m/s (8530 ft/s) 76 68 60 43 32 22 13 8
OQF 2 pdr AP* 0 2800 m/s (9186 ft/s) 82 76 67 49 35 27 19 12
OQF 2 pdrAPC 0 2600 m/s (8530 ft/s) 68 62 56 41 31 23 13 8
OQF 2 pdr APCBC 0 2600 m/s (8530 ft/s) 74 70 66 57 48 42 33 26
OQF 2pdrLittlejohn Mk I 0 4200 m/s (13780 ft/s) 125113 99 73 51 35 25 15
OQF 2pdrLittlejohn Mk II 0 3750 m/s (12303 ft/s) 111105 99 85 72 63 55 47
OQF 6 pdr AP 0 2800 m/s (9186 ft/s) 104 96 88 70 54 42
OQF 6 pdr AP 0 2925 m/s (9596 ft/s) 113106 98 81 66 53
OQF 6 pdr APC 0 2775 m/s (9104 ft/s) 104 96 88 70 54 42
OQF 6 pdr APC 0 2900 m/s (9514 ft/s) 109102 94 77 60 45
OQF 6 pdr APCBC 0 2600 m/s (8530 ft/s) 100 95 91 82 72 65
OQF 6 pdr APCBC 0 2725 m/s (8940 ft/s) 106102 97 88 78 70
OQF 6 pdr Sabot 0 4000 m/s (13123 ft/s) 161153145127109 94 77 62
OQF 77mmAPC 0 2600 m/s (8530 ft/s) 143137131116101 91 78 66
OQF 77mmAPCBC 0 2575 m/s (8448 ft/s) 143137131117104 98 90 84
OQF 77mmSabot 0 3675 m/s (12057 ft/s) 198193186160143123103 83
OQF 17 pdrAP 0 2900 m/s (9514 ft/s) 151143137123109 97 84 71
OQF 17 pdrAPC 0 2900 m/s (9514 ft/s) 151143137123109 97 84 71
OQF 17 pdrAPCBC 0 2900 m/s (9514 ft/s) 172166161148136125114103
OQF 17 pdrSabot 0 3950 m/s (12959 ft/s) 233226219200182162143123
OQF 25 pdrAP 0 1550 m/s (5085 ft/s) 79 74 69 61 54 49
OQF 25 pdrAP 0 2000 m/s (6562 ft/s) 104 98 91 76 65 56
OQF 95mm/L20HEAT 0 1650 m/s (5413 ft/s) 127127127127

Entire data collection each individually normalized to RHA hardness of BHN 270 and US NBL criteria.
British MQ homogeneous armor seems to be equivalent quality to 250 BHN in testing.
*  AP 2-pdr shot may shatter vs 2 x caliber armor above 2600 ft/s.

There are a few anomalies in the data like why does the OQF 17-pounder have considerably better penetration for the APCBC than the APC and AP?  A windscreen and AP cap should theoretically reduce the penetration slightly.   But early war tests were sometimes revised later war because methods changed or ballistics measurements improved.  To normalize data I had to dismiss some early war data in favor of revised late war data.

NAAB2 does include the 3" OQF 17 pdr in British gun class 13.  Change shell quality to 0.985 and set to meters.  Armor deck British post 1930.  The Ballistics page produces result very close to the above table for 17-pdr APCBC.