Adapting the design to fire the standard .303 British round led to the Rifle, .303 Pattern 1914 (P14), a design fed from a five-round internal box magazine. With its prominent sight protection ears on the receiver, "dog-leg" bolt handle and "pot-belly" magazine, it was distinctive in appearance. The action was essentially a Mauser design with some Lee–Enfield features and optimised for rapid fire, with the action cocking on closing, a feature highly valued by the British Army with its emphasis on riflemen highly trained for rapid fire, but less valued in other armies, such as the US or Germany, where cock-on-opening designs such as the M1903 Springfield and Gewehr 98 were preferred. Cock-on-opening actions became more difficult to operate when heated by rapid fire as the effort to open the bolt had to overcome the striker spring to cock the action as well as unsticking the fired case from the chamber. The P14 was an advanced design for the time, and was said to be the most advanced service rifle of World War I.