I own a recently purchased, de-activated, Browning M1919 M.G. ex Venezuelan army and dated 1950 manufacture in Belgium. It is in good used condition with full matching serial numbers but the only reference to it's calibre that I can find on it is 7.65mm stamped on the breech block. Does this mean that it is the original 30 cal which it was sold to me as or is it 7.62mm Nato or perhaps another less common calibre??? Thank-you for any information.