The primary contractor (Vickers
) was unable to produce more than a handful of rifles, so the P14 became a de facto
afterthought. The Short Magazine Lee–Enfield
therefore remained the standard British rifle during World War I and beyond.
The need for additional small arms combined with a shortage of spare industrial capacity led the British government to contract with U.S.
commercial arms manufacturers, Winchester
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. 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. Shortly afterwards a modification was made to enlarge the bolt lugs and the rifle became the Mark I*. However, each factory produced slightly differing parts, leading to interchangeability issues; Winchester was particularly troublesome in this regard, going so far as to refuse for months to change to the new Mark I* standard. Therefore, the official designation of the rifle was dependent upon its manufacturer: e.g., the Pattern 1914 Mk I W
and Pattern 1914 Mk I* W
is a Mk I or Mk I* of Winchester manufacture, R
would be Remington, or E
The P14's principal combat use during World War I was as a sniper rifle, since it was found to be more accurate than the Short Magazine Lee–Enfield, either in standard issue form or with modified "fine-adjustment" aperture rearsights designated Pattern 1914 Mk I W (F)
and Pattern 1914 Mk I* W (F)
or, from April 1918,
Aldis Pattern 1918 telescopic sights designated Pattern 1914 Mk I* W (T)
(modified and telescopic sights were mainly used on Winchester-manufactured rifles, the Winchesters being thought to be of superior quality).
Eventually Winchester would manufacture 235,293 rifles, Remington 400,000 and Eddystone 600,000, totaling 1,235,293 rifles.