This is a .300 H&H Magnum standard barrel, manufactured sometime between the years 1955 and 1957.
Bluing - 98% - This barrel shows minimal signs of wear.
Metal - Overall, this barrel is in excellent condition. There are some very minor scratches, but no notable nicks or other forms of metal damage.
Bore - 5/10 - The bore shows some signs of wear. The rifling is bright and smooth throughout the length of the barrel, but there is a consistent amount of light pitting throughout the entire bore. Borescope verified.
We use the NRA Modern Gun Condition Standards Grading System for grading part conditions. You can read about it HERE