Well, several errors in that. Let's look at the history. The British decided well before WWI that the Mk III SMLE was outdated and they needed a more modern rifle, and designed one based on a combination of the Mauser 1898 and the U.S. M1903 Springfield, with some additions to suit their own needs. They chambered it for a new cartridge, the .276 Enfield. Contrary to what has been written, the .276 Enfield was NOT the .280 Ross; they are very different cartridges, though the .276 Enfield was intended to match the ballistics of the Ross cartridge, which was the darling of the high-velocity crowd at that time.
In any case, the result was called the Pattern 1913, or P-13. As war approached, the British decided that it was not a good time to change ammunition, but they still wanted to keep the new rifle, so they dropped P-13 development after a few thousand had been made and modified the design to use the standard .303 cartridge, calling the rifle the Pattern 1914 or P-14.
The change was made easier by the fact that the .276 Enfield is a very fat cartridge, over 1/2 inch at the base, with a rebated rim, so the magazine could be used with the rimmed .303 without modification.
When war came, the British decided not to produce any more P-14's, and devote their factories to production of the SMLE. But they contracted to three American companies, Remington, Winchester, and a new entity, associated with Remington, to make the new rifle for them. The three factories, at Ilion, NY, New Haven, CT, and Eddystone, PA, produced a total of 1,117,850 P-14 rifles.
Just about the time the British contracts were completed, the U.S. entered the war, with a severe shortage of M1903 rifles. So U.S. Army Ordnance contracted with the same companies to modify the P-14 to use the U.S. .30-'06 ammunition; that rifle was the U.S. Model of 1917. No P-14's were "converted" to use the U.S. cartridge - Model 1917's were new rifles.
1,235,298 Model 1917 rifles were produced and it was the most common rifle in the American Expeditionary Force. After the war, Army Ordnance, for whatever reasons, took the somewhat controversial step of storing the Model 1917 rifles and continuing to treat the M1903 as the standard rifle.
At the onset of WWII, when Britain was under attack, President Roosevelt ordered some 1.1 million Model 1917 rifles sent to England. That was before the Lend Lease act was passed and the action probably was, strictly speaking, illegal.
Since Army Ordnance had considered those rifles to be a good part of the war reserve, and production of the new M1 rifle was then a trickle, they hurriedly contracted with Remington to manufacture the M1903, using tooling from Rock Island Armory that had been in storage.
Jim