It is NOT a Breda MG definitely.


Maraz

The type of H.E used on the breda 12.7 ammo is PETN!(pentaerythritol tetranitrate, also known as pentrite, or rarely and primarily in German as nitropenta) is one of the most powerful high explosives known, with a relative effectiveness factor (R.E. factor) of 1.66. It is more sensitive to shock or friction than TNT or tetryl, and it is never used alone as a booster. It is primarily used in booster and bursting charges of small caliber ammunition, in upper charges of detonators in some land mines and shells, and as the explosive core of detonation cord. (source wikipedia)

The type of explosive used explains the large explosive burst. This though has nothing to do with actual damage sustained as hitting power is lower than other 50 cals.When used against fabric covered aircraft it was extremely effective.Hence the large number of italien bi-plane aces in Spainish civil war!