The Mahdi of the Sudan was able to defeat British-Egyptian armies equipped with machine guns using troops armed with sticks and stones.

The finding

What the evidence shows

The Mahdist forces did win major victories against Egyptian armies that had machine guns and artillery, most notably wiping out Hicks Pasha's expedition at the Battle of Shaykan in 1883, where about 7,000 Egyptian troops were killed. But the Mahdists were not armed with sticks and stones, they fought with rifles captured in earlier battles along with swords and spears, and Hicks's force was Egyptian led by a British officer rather than a true combined British-Egyptian army. At the later Battle of Omdurman in 1898, machine guns under Kitchener devastated the Mahdists, so the claim only holds for the earlier fights and overstates how primitive their weapons were.