Showing the details of the shells used(where known)
Oerlikon 20mm L/70 (Anti Aircraft)
Maufactured in Switzerland the first British imports arrived in 1940, and subsequently manufactured under licence in Ruislip London later in 1940. Two versions were manufactured with different barrel lengths L/70 and L/85 which gave muzzle velocities of 820m/sec L70 and 1050m/sec L/85. The L/70 could deliver shells at 450rpm and the L/85 at 900-1000 rpm.
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.