they exist, I bought one for my dad. he has a browning bar collection. he has all the oddballs... 270 wby 280 rem, 243 and 308s with bosses, I asked a browning rep at a nra show once about the 280 and 270 wby and he told me that despite what the books say, they were produced for less than 3 months and less than 1000 of each caliber were out there, who knows if he was right but good luck on your search
