These are 12,7 x 80SR Breda HEI rounds from the spanish civil war. They were used in airplane machine guns.
The yellow one is (BPD 37 S) and the red one is (BPD 39 S), the S indicating the explosive nature of the projectile (Scoppiante = Explosive).
Cases with this headstamp style were reloaded with ball bullets in Spain after the war, and probably during the war also. The “S” was sometimes confused with “Sevilla”.
What I cannot recall is the meaning of the red lacquer in the second projectile; my memory ain’t what it used to be and my memory ain’t what it used to be. Maybe the red lacquer indicated a self-destroying projectile. Any ideas?