I have two 6BR's. One is in a Remington 722 with a 20" medium sporter contour the other is an XP-100 with a 15" medium / heavy barrel. The XP-100 is the most accurate gun I own Period. The barrel on the Xp started out as a Golden State Arms barrel that was a 243. I had it shortened, rechambered and insalled on the XP action. I shoot it in IHMSA silhouettes half scale and have not missed a target in a match in three years. I only shoot it twice a year but it is always up to the task.
I have not done much testing since I found a good load right away, and it does better than I ever expected. The rifle is a little more picky but works great as a short light deer rifle. I would have loved for Remington to chamber the 6BR in a Classic but that would have cost me some dough.
I say get one and enjoy yourself, I love both of mine. It's all about what you want to use it for. I think is is very efficient even in a short barrel and if you want a truely fun cartridge the 6BR is a great one. Light recoil, great accuracy and plenty of punch for deer to at least 200 yards with the right bullet. Buy Lapua brass, it's expensive but it is the best brass I have ever seen or used.
Joe