I can't answer for the first post, but I have seen, and did own, a Lee Enfield rifle chambered for the unusual 8x56R, not 8x50R, cartridge. The one that fired a very long and heavy bullet of over 200 grains. From memory it was made on a No4 action. Bizarre! Needless to say it was never fired by me as availabilty of ammunition was practically nil!