This addition would be quite nice to the Stuka here in AH.
I have seen gun footage of this weapon used against T-34's while watching The History Channel. The T-34's did not make it. lol Wings of the Luftwaffe, if I recall the program's name correctly. That wasn't the only program shown with gun footage of the Stuka using the BK's though. But it's just one that springs to mind. It has been a long time since I've seen it, so I could very well be wrong.
Some info regarding the BK 37:The Bordkanone BK 37 ((on-)board cannon 37) was a 37mm anti-tank/bomber autocannon based on the earlier 37 mm Flak 18 made by Rheinmetall. It was mounted on World War II Luftwaffe aircraft such as the anti-tank or bomber-destroyer versions of the Junkers Ju 87D-3 and G-2, Henschel Hs 129B-2/R3, Messerschmitt Bf 110G-2/R1-3, and others. The cannon could be attached under the wings or fuselage of the aircraft as a self-contained pod with a 12-round magazine. It fired APCR (Tungsten hard core) ammunition or high explosive shells in 37x263B mm caliber at 160 rounds per minute.
I pulled this info off of the link below.
http://en.wikipedia.org/wiki/BK_37According to the info here, it is telling me that the BK 37 carried a 12 round magazine. They probably loaded a round into the gun prior to loading the 12 round magazine, meaning each gun would have 13 rounds for a total of 26. But in our case, we would only have 24 rounds total.