A question from  hrafn in the Hangar: "How do the 20mm cannons differ between allied/axis aircraft in WWIIOL? Does one have a faster rate of fire? Does one cannon do more damage than the other, based on type of round?"

DOC: All the ammunition in Battleground Europe is modeled to reflect their real life differences, as all ammunition even of the same or similar caliber was not identical. For example the 20mm MGFF cannons on the earlier German aircraft like the Bf109E-4, Bf109F-1 and Bf110C-4 had a lower muzzle velocity and slower rate of fire than the later MG151 20mm cannon you find on the Bf109F-4 and Bf110F-B. In this case we’re talking about the 20mm cannons serving on the same side being different based on what historical type they were.
 
When we look at the guns employed by different sides the variations are no less significant. For example the Hispano 20mm cannon that some French and some British aircraft use had a higher RoF than the MGFF 20mm cannon, but not as high a RoF (rate of fire = number of rounds fired per second) as the later MG151 20mm cannon. Rate of Fire will affect how many rounds will impact your target (given your aim is good) in a given timeframe, and this affects how quickly you can reach predetermined damage levels to knock the target aircraft down. Remember to factor in another variable that being that if a gun fires through the propeller arc then it will generally have a lower RoF than the exact same gun which doesn’t need to be synchronized to the spinning propeller blades. This of course doesn’t apply to cannons firing through the spinner itself.
 
Additionally, the ammunition each type of gun fires will vary in mass as well as the mV (mV = muzzle velocity). Both mass and muzzle velocity will affect the kinetic damage potential of the round when it hits a target. The Hispano rounds are generally heavier and traveling faster than the German 20mm ammunition. The MGFF 20mm rounds are on average the slowest while the Hispano 20mm rounds are the fastest. The MG151 20mm rounds are closer to the Hispano in mV than the MGFF and thus better than the MGFF rounds.
 
Higher velocity rounds are also easier to aim having a flatter ballistic trajectory. Finally there is explosive content and in this regard the German 20mm Mine rounds had the most explosive content of all, but the British Hispano 20mm HE round was better than the average German regular HE round  because it was heavier and traveling faster than the lighter HE and HE-T rounds that the Germans used. Shrapnel consequences after the HE rounds have exploded also vary in speed and mass depending on all these factors and the variations they contain. The German 20mm mine rounds differ from regular HE rounds by having a drawn casing which is thinner and allows more explosive to be placed inside a given caliber (diameter) of explosive shell.
 
While I have framed this reply in the context it was asked (pertinent to aircraft 20mm cannons) it should be applied to *all* the guns in Battleground Europe, because they are all different in many ways. The 75mm cannon on the German PzKw.IVg is a much more deadly gun than the 75mm cannon on the Sherman M4a2 because it has a higher muzzle velocity. Of course, a lot depends on what kind of armour your target has (if you’re a tanker) and in this regard all the tanks vary from each other just like they did in real life, which is from where we draw the data that we used to model them. This creates an enormous number of outcomes that are very hard for players to predict accurately all the time because of the sheer number of variables affecting the result, many of which they can’t really be sure of. Did I hit that tank at 32 degrees off or was it 46? Was it a road wheel or just the track plate? Did it penetrate and if it did which crew member inside did it wound or injure? Will the ammunition cook off? Is the gunner still alive and about to shoot back at me or did I wreck his gun?
 
If you really think about it, the sheer number of possible outcomes of ammunition based impact damage in Battleground Europe is so high a number that you’d probably never experience every possibility no matter how much you play the game. Like war itself, fact is often stranger than fiction.