When World War One began, the British did not have a formal sniping program, and by 1915 the British found themselves thoroughly outclassed by the Germans in this area. They responded by developing tactics and equipment for sniping, and by mid 1916 they had really outclassed the Germans. However, the mid-war British sniping rifles really left a lot to be desired, even if they were being used effectively in the field. There was no single military optic, instead a wide variety of commercial scopes were rounded up and put into use. The mounts for these scopes were offset to the left side of the rifles to allow for continued use of stripper clips. Clips were arguably not really necessary on these rifles, and the offset scopes led to substantial headaches in use, as they required calculating windage as well as elevation adjustments depending on range.
Through 1918, though, the British developed one of the best sniping rifles of the war, although it would be introduced too late to see virtually any front line service. This new rifle was a Winchester-made Pattern 1914 Enfield with a center-mounted optic, and was designated the P14 MkI W(T). The P14 rifles were more accurate than the SMLE, and the centrally mounted optic made for much simpler shooting. These rifles were deemed to be mechanically capable of 1.5 MOA shooting, with the practical expected group size being 3 MOA.
Three thousand of these P14 snipers' rifles were assembled and kept in service after the end of the war, but in the mid 1930s a small additional batch of 79 were made for the Irish Free State by BSA. These were all eventually surplussed to the US, and the rifle in this video is one of those late-production guns.
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