Lucite, from these 4x pages, can I reasonably assume that you aren't a technical sort of person........... In much the same way as I'm not a computer person!

You can be rest assured, in the nicest possible way, that 800 grit is going to be hard pushed to chamfer a fingernail, let alone chamfer a block of tough steel that has been case hardened to boot. Attack it with a grinder as shown by Parashooter

Other forumers also take note that the front magazine lips should be absolutely and totally clear of the barrel of the bolt. They are simply to hold the nose of the bullet until it strikes the feed ramp and THEN, that action unhooks the bullet from the left or right lip and leaves the nose of the bullet to wend its weary way up the feed ramp and into the chamber.

If the front feed lips can be forced up so as to touch the bolt body then it indicates that the magazine is defective where the top front edge contacts the MAGAZINE STOP FACE at the front of the magazine well OR that the actual magazine stop face in the body is worn away. Yet another defect that will ZF a No1,4 or 5 rifle