Painful, sore, red gums can be a symptom of gingivitis (inflammation of the gums) or, more likely, periodontitis (inflammation of the attachment fibers of the teeth and supporting bone), which can arise due to a number of different causes.
klick (plural klicks) ( 1 slang, military) A kilometer. 2002, Robert J. Sawyer, Hominids an asteroid between one and three kilometers wide had slammed into the ground at fifteen klicks per second. ( 2 slang, usually in the plural) Kilometres per hour.
If you're looking at a target 100 yards away, four clicks will move the bullet's point-of-impact one inch. The principle is the same for those scopes having 1/8 MOA per click -- it takes eight clicks to equal one MOA, and when your target is 100 yards away, those eight clicks will move the point-of-impact one inch.