i have a 300 wby mag in a colt sauer how would i tell how old it is

Have you been to coltsauer.com? Seems like these guys are pretty focused historians for your rifle, and you might be able to find your serial number range on their front page, without any other research. If it's not on the front page, I'd encourage you to email or call them, as I bet they can help you on your quest.

thanks I will try that