Barrett currently orders the new 4.5-14x50 LR M1's for the 82's. If you have access to older Time magazines, look at the April 7th, 2003 issue on page 24 & 25 you will see a couple of Special Forces guys with the 12-40x60 Leupold Gold Ring Spotting Scope and the Barrett 82 with the 4.5-14x50 LR (M1 is new, so this was the old standard target model).
Hope this helps.