The Second Battle of Bauche.
From the whole timeline of the Mexican Revolution, most narratives punt when it comes to the breakdown between the Orozquistas and the Maderistas. After all, the historian still has to explain why Carranza couldn’t reconcile with Zapata and why Obregon eventually mowed down Villa’s Dorados with heavy caliber machine guns. Or why Obregon felt he had to take out Carranza and then, about those who felt it was their Christian duty to put a bullet into Obregon's head. So it seems a small affair in the big picture, that the gente de Orozoquo felt that they had to trade shells with the gente de Madero.