The Sarco 1917 Enfiels look like they have a notch cut out of the receiver ring. They may be from drill rifles which were rendered inert. A 1917, 1914 Enfield and a Remingto 30 or 30S can be made into great magnum rifles. When I was in Mumbai last year I dropped by a gun store where they had a .375 H&H build on a 1914 Enfield. Very nice.