The Battle of Omdurman is one instance that stands out. It took place in Northern Africa in 1898 and was a battle between British forces and the army of Abdullah al-Taashi. The British had repeating rifles, artillery, and, most importanly, the machine gun. The othe side was equiped with arrows, spears, and some old muskets. Abdullah al-Taashi's side suffered upwards of 10,000 deaths, while the British only suffered 47 deaths. The colonization is full of instances like these, in which advanced European countries vanquished the lesser technologically advanced African natives.

Source: Brighton, Terry - The Last Charge: the 21st Lancers and the Battle of Omdurman