The need for additional small arms combined with a shortage of spare industrial capacity led the British government to contract with United States commercial arms manufacturers, Winchester, Remington and Eddystone (a subsidiary of Remington set up principally to manufacture the P14) to produce the P14 for the British before the US entered the war in 1917. However, each factory produced slightly differing parts, leading to interchangeability issues. Therefore, the official designation of the rifle was dependent upon its manufacturer: e.g., the Pattern 1914 Mk I W is a Mk I of Winchester manufacture, R would be Remington, or E for Eddystone. Problems were encountered with specifications, quality and shortage of machine tools and skilled workers, with the result that the first rifles were not accepted by British inspectors until February 1916. In December 1916, a modification was made to enlarge the bolt lugs and the rifle became the Mark I*. They were still designed by the letter of their manufacturer (W, R or E), even if the production had become more standardized. The Mk I were soon confined to training usage and marked "DP", meaning Drill Purpose.