Instructions
Inspect the buttstock of the rifle. If it features a brass disk on the right side, it was manufactured for the UK infantry, if no such disk is present, it was manufactured for the United States.
Inspect the rifle for any markings designating the caliber. If it is marked as a .303 it was probably manufactured for Enfield. If marked as a .30-06 it was manufactured for the United States. If it is marked as a .303 but has no brass disk, it may have been rechambered at some point in its history. If the rifle is a .30 caliber and has a red strip painted on the buttstock, it was manufactured in the United States for use by the British Home Guard during World War II. If the weapon is marked as a 7mm, it was manufactured for sale to Honduras in the early 1930s.
Inspect the rear aperture sight. If there are no heave metal pieces ("ears") on either side of the sight, it is most likely a Remington M30. These rifles were manufactured in the interwar period to much the same specifications as the M1917 as sport rifles.