The Ram Mk I, it was based on the fully tracked RAM chassis and was in use from 1941 to 1942. General Details (Medium Tank) Specifications Operational Date(s) 1941 - 1942 Ordnance classification Quantity Produced 50 Weight unknown Crew 5 M.G's small 3 M.G's large(>10mm) n/a Length 5.85 mtr Width 2.90 mtr Height 2.69 mtr Engine Details/Performance Max Road Speed 25 mph Max Cross Country Speed 20 mph Range Road 144 miles Range Cross Country 57 miles Fuel Type Petrol Fuel Capacity 175 gal Horse Power 400 hp Power/Weight unknown General Information The Ram Mk I, it was based on the fully tracked RAM chassis and was in use from 1941 to 1942. It was armed with 3 light machine guns. Its main armament consisted of an Ordnance Q.F. 2pdr weighing 0.860 kg and with a maximum range of 5,900 metres. The Ram I Cruiser tank was developed by the Canadians utilising the engine and drive chain from the American M3 Grant with a new cast upper hull and turret. Originally designed to take the 6pdr gun, these early models had a 2pdr gun as the 6pdr wasn't available in time. Fifty of these vehicles were produced between Autumn 1941 and early 1942 by the Montreal Locomotive Works, most of which were shipped to England. The vehicle transmission sprocket was at the front, the track passed under 6 road wheels on three bogies to the rear idler, then return via 3 return rollers. Armour Details Turret Front 87mm @ 47° (128mm) Side 63mm @ 5° (63mm) Rear 51mm @ 5° (51mm) Top 22mm @ 90° (22mm) Superstructure Front 87mm @ 45° (123mm) Side 63mm @ 0° (63mm) Rear 38mm @ 0° (38mm) Top 13mm @ 87° (13mm) Hull Front 87mm @ 45° (123mm) Side 63mm @ 0° (63mm) Rear 38mm @ 0° (38mm) Top 13mm @ 87° (13mm) Armour (x)mm @ (y)° (Effective mm @ 0°) Effective Armour - Maximum 128 mm - Minimum 13 mm Weapon Details Ordnance Q.F. 2pdr (Anti Tank Gun) History Used both as an Anti Tank gun and as a Tank gun the 2pdr was first used in Belgium in 1939. The majority of the British guns were captured by the Germans at Dunkirk. However the 2pdr manufacture was continued but was slowly replaced by the 6pdr from 1942. Manufactured 1936 - 1944 Calibre 40mm Length L/50 Rate of Fire 22 rpm Ammunition Details Name/Id Calibre Weight MVelocity Explosive Content AP/T Mk I (AP Armor Piercing) 40mm 1.08Kg 792M/Sec Quoted Penetration 53mm@455m Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.26 0.54 1.16 1.85 2.61 3.44 4.32 Penetration(mm@30°) 58 55 49 40 32 26 20 16 Penetration(mm@0°) 68 64 58 46 37 30 24 20 Hit Probability(%) 79 79 76 71 55 30 20 6 HE/T Mk II after 1942 (HE High Explosive) 40mm 0.86Kg 792M/Sec 0.085Kg explosive Maximum Range not shown as gun elevation is limited Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.26 0.54 1.16 1.85 2.61 3.43 4.31 lateral dispersion means the side to side variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 0.12 0.12 0.12 0.21 0.32 0.43 0.53 0.64 80% of shells land within +/- (mtr) 0.15 0.15 0.15 0.27 0.41 0.55 0.68 0.82 95% of shells land within +/- (mtr) 0.24 0.24 0.24 0.41 0.63 0.84 1.04 1.25 range dispersion means the back to front variation of the shell from the aiming point 50%(CEP) of shells land within +/- (mtr) 0.15 0.15 0.15 0.27 0.40 0.53 0.67 0.80 80% of shells land within +/- (mtr) 0.19 0.19 0.19 0.35 0.51 0.68 0.86 1.02 95% of shells land within +/- (mtr) 0.29 0.29 0.29 0.53 0.78 1.04 1.31 1.57 Direct Fire Range(Mtr) 100 200 400 800 1200 1600 2000 2400 Flight Time(Secs) 0.13 0.27 0.56 1.21 1.96 2.79 3.69 4.66 Hit Probability(%) 79 79 76 71 55 30 12 6 Blast/Fragmentation Effects Burst radius Infantry in open 99% kill 1 mtr Burst radius Infantry in open 66% kill 3 mtr Burst radius Infantry in open 33% kill 9 mtr  Armour Penetration inc roof at 1 mtr 0 mm An explosion within 1 mtr of infantry in the open will cause 99% casualties - lethal. An explosion within 3 mtr of infantry in the open will cause > 66% casualties and could damage some AFV's. An explosion within 9 mtr of infantry in the open will cause 33% casualties. The blast effect of this shell exploding within 1 mtr of an armoured vehicle will not cause any significant armour damage. About Penetration Figures All penetration figures in this database are calculated to a common standard based on German WWII testing criteria (complete penetration with functioning fuze). This allows direct comparison between all nations' guns. Original national test figures would be higher for some nations due to different criteria: German: 1.00? (baseline - strictest) British: 1.02? (slightly looser) American: 1.05? (50% mass through plate) Soviet: 1.10? (75% mass through plate) For example, a Soviet gun showing 159mm here would be published as ~175mm in Soviet documents, and a German gun showing 120mm would be published as 120mm in German documents. The 159mm figure is directly comparable to the German 120mm - the Soviet gun really was more powerful. National Testing Standards German: 1.00? - Complete penetration, fuze functions (strictest) British: 1.02? - Complete penetration American: 1.05? - 50% of shell mass through plate Soviet: 1.10? - 75% of shell mass through plate All database figures are normalized to German standard for direct comparison. Multiply by the factor above to see original national test figures.

Hit probability is based on a static 2 x 2.4 metre panel at 0 degrees(vertical) at the range specified.

The data that has been used to create these records has come from Wikipedia, The Lone Sentry, The Bundes Archive and numerous books and websites that have provided the detailed information that has not been available anywhere else. The information we use to calculate the penetration tables, flight times and the hit probability comes from the Gun Calibre, the Shell Mass(Kg) and the muzzle velocity, plus range reductions to allow for gravity and wind resistance. This calculation originally came from a pre-war Krupp calculation which has been modified, and seems to fit the actual test results.

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