Just For The Record

Only one of these rifles is an Enfield.  That would be the one on the bottom.

It's a Rifle, Short (Magazine) Lee-Enfield Mk III* and was actually made at Royal Small Arms Factory (RSAF), Enfield in 1915.

The younger gun, made in 1917 at the Eddystone facility of Remington Arms Company, is not an Enfield.  The design comes from Enfield via a circuitous route, but RSAF didn't actually make any.

The M-1917 rifle came to be when the British realized that with an encroaching war they weren't going to be able to do two things: switch to .276 Enfield, or shut down production of Lee-Enfields to transition to making the P.13 rifle.

They did manage to get the design into production by changing it to .303 British and getting Winchester and Remington to make them, with Remington making them at two facilities; Ilion, NY and Eddystone, PA.  That is the P.14 rifle (technically Rifle Pattern 1914 Mk I and Mk I* with an initial of W, R or E for each factory).

Once the run of P.14 rifles was made the US found itself in a similar bind with regards to rifle production.  They were making all of the M-1903's they could and still needed more guns.  It was bad enough that they type standardized the Mosin-Nagant Model 1891 being made by Remington and New England Westinghouse as the Rifle 7.62mm M-1916 and left it in 7.62x54mmR!

Because the P.14 was derived from a rimless Mauser action in the first place, it was relatively easy to switch it to a different rimless cartridge, our .30-06.

This went into production as the Rifle, .30-caliber, M-1917.  It was, in fact, our primary service rifle for the Army in World War One; despite being a secondary standard.  It is also the finest six shot (6+1) turn-bolt rifle the Army ever issued!