Thank you so much, Greyman! Your reply (already informative in itself) disclosed me a world of news! Started searching for differences between the two incendiary (blue body and white tip) and found this:
Breda ammo (12.7mm and 7.7mm)
summarizing:
White tip looks to be APIT.
It seems there isn't a "blue body" but a "blue tip" I.
Also interesting:
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First, the RA lacked any kind of standatization and pilots could choose their own belt, but on a book on the Re 2001 a pilot describe the belt for the .50cal as "mixed shells of armor piercing, tracer, explosive and incendiary. worth to note is that he calls that belt "very effective" and that the british "envied the HE shell">>