TY for saying do sabre, couldent of done it without your input:)
HFMudd, one thing I am not shure your "q" factor is factoring, is that the Italian 12.7 used HEI rounds, so they contain chemical engery. The idea is this if the round can cary some explosive engery to the target than it nead not be so heavy. Also most air to air combat took place at around 400 yards so the lighter and shorter ranged rounds of the Breda are realy in keeping with a different aproach to air to air weaponary, than say that of US rounds and guns. Having said that, by comparision Italian fighters(except series 5 planes) were typicaly armed much like Japanese Army fighter, two 12mm and two 7mm guns all firing primarly chenical engery weapons, HEI or Incendary rounds, even the 7mm rounds had a chemical filling. Now this subject has been debated at length but it is generaly considered that the Breda type rounds would have a good damaging effect do to thier design. Howeaver differing some what from the US 50 cal type weapon which primarly fired a solid AP type round. The solid ap type rounds were intended to defeat the piolet and the engine, while the HEI type rounds were more intended to defeate the plane, it's controll surfices the fuel tanks the airframe by blowing off chunks and seting it afire. The heaver AP rounds pentrated deaper, while the HEI rounds blew chunks off.
Somewhear their is a link showing a 202 on a P40's 6 just wasting it, you can chunks falling off as the rounds hit, old gun cam fottage very cool.