Remington .303 British Box

Recently acquired this Remington Arms Company .303 British “White Box”. Code inside end flap is R27C, which, if my information is correct, indicates 1939 (too early in my opinion), 1948, 1959 or 1970 (too late based on headstamp). Headstamp is REM-UMC 303 BRIT Military contract for someone, it would appear. What say you?



Have the same box & contents but end flap code is “T28Y”
Red annulus, nickel primer & the thumb cut is on the right side. Looks as if yours was printed up-side down? The rare version!!