What sort of ammunition did Maxim Machine Guns use in WW1?

Primarily British .303 but they were chambered in other calibers based upon what country was using them. 8x57, 7.62x54r and 30-06. Many countries used it or variants of it so there are going to be made in A LOT of calibers. But those were not made by Maxim. Usually by others copying the design.