Most shooters use the 6BR for the 300 meter F(O) class. If I'm serious about winning, I use a 308 which as it happens, is also eligible for F(TR). The 308 is no handicap though it is somewhat more difficult to shoot due to recoil. Much less commotion with the 6BR.
Using the 6BR, I once had to fire an extra shot because the scorer didn't notice the rifle move and wasn't paying attention to the target. The previous shot was an "X", the shot he didn't notice was an "X", and the extra shot I had to fire was, luckily, an "X". The point is, 6BR's are very easy to handle and shoot very well. I can't say why I don't use mine more often.
I toyed with the idea of building a 22BR which I think would work quite well but ended up building a 22-250 instead. I'll use it this coming weekend at Homestead. Seems like it will work reasonably well but I don't expect barrel life to be real good (80 gr bullets at 3375 fps).
Good shooting guys. Sorry I couldn't make it. Regards, Bill