I've spent some time reseaching some information on the M2 .50 used in US aircraft. First off I want to say to HTC WTG it looks like you got this one right. Now, for everyone to understand this it will be detailed so if I sound as if I am going to indepth, sorry. The biggest thing you must remember when dealing with weapons and munitions is what you see in the movies is for the big screen. What we're talking about here is muzzle velocity. Due to the short barrels in the wings the ammunition cannot obtain full powder burn. So, your .50's and other "rifle" cartridges are only getting from 500 to 800 foot pounds. Most pistol cartridges achieve up to 1100 so, you can see where distance, accuracy and power is greatly reduced. When you use these calibers with proper barrel length you'll acheive the 2000+ you'd expect from them. This is partly why cannons became a must. Not because their ballistics where any better(only slightly, 1300 to 1800) but, because they were equiped with explosive charges. Airplanes that had weapons in the cowel or through the prop driveshaft faired better results due in fact to longer barrels and better ballistics.
Using this knowledge and pilot experiences you'd want to get close and use shorter convergences. Shot placement is probly the biggest key. According the Luftwaffe reseachers all the rifle calibers to include the .50 would just punch little holes in the plane unless it hit the pilot or engines. The cannons were made to punch through and explode causing great damage. Thats why every german plane had a cannon. Early in the war the British had a problem with their cannons. The fuzes weren't quite right the cannon shells would explode before or pass through and explode. So, they went to AP rounds which meant they were back to shooting at the pilot or engine agian.
Ok, now that I've opened this hornets nest have at it!
