The Winchester model 100 was shipped fromt he factory during the 1961-1975 time frame. It was originally offered in .243 and .308. with a 22" barrel and .264 with a 19" barrel. 308 and 243 could also...
That could prove to be very difficult due to the age of the winchester in question.I would start my search at numrich gun parts corp.They may be found on the web.If you are not sucessful I would look...