Wheel bearing grease is hi temp due to proximity to a cars brakes, which can get quite hot.
That said, there's nothing wrong with using it on the rails of a semi auto. Overkill, but it won't hurt a thing.
Using it in other places would depend on a number of factors that the lubrication industry calls LETS, an acronym for load, environment, temperature and speed. In other words, you'd need the tech data sheet for the grease you have, and using LETS, compare it to the application to know if it's suitable. Using the wrong grease in an application will lead to any number of unpleasant consequences, all starting with failure.
Ignore the color of any lubricant, it's not an indication of any attribute other than that was the color the mfr chose to use. The color is there due to the manufacturer putting dye in it so they can identify it in house (in a natural state, most greases look alike), not because of any quality formulated into the lubricating properties.
Last edited by Fleet; June 12, 2012 at 08:32 AM.