Complex sentence: Scott's platoon's leading section when approximately 300 yards from the village came under attack by machine gun fire and grenades; he immediately went forward and firing his sten gun inflicted many casualties amongst the enemy who were forced from their position.
Split into simpler sentences: Scott's platoon's leading section when approximately 300 yards from the village came under attack by machine gun fire and grenades. He immediately went forward and firing his sten gun inflicted many casualties amongst the enemy who were forced from their position.