I have a Remington XP-100, 221 Fireball that I am curious about the value. It has a 4-digit serial number 86XX and the same number is etched on the bottom-back of the bolt. It has a 7.5 Leupold scope and has never been used in competition, so there arer not a lot of rounds through it. It is awesome at 100 yards. I don't have any pics of it, seems to be synthetic stock or a type of plastic. I believe it was manufactured in the mid 60s. Any help or if you need more info, please let me know. Thanks Looper.