Just saw this thread and thought I would comment. I broke my ankle recently, so I am sitting at home recovering for a few more weeks.
I have done more work with the 6.5 than most anyone that I know of. Had some good luck earlier on, like Randy said, with a 6.5 BR, 12 twist Krieger, my own or Bill Browand's 95 grain bullets. The problem I had was with getting good scoring. I laid off it for quite a while, on and off, and picked it up again last year, but for score only.
I also got a real good set of dies, made by a friend, that gives me true benchrest quality bullets. The problem with making bullets has always been getting good jackets. We had J4 talked in to making some .900 jackets at one time, but I couldn't buy enough at a time to keep them happy. They ended up scrapping the remains of the lot. I have a few left over jackets to make a few more bullets, but without good jackets, there is no way to expand the interest.
My best set up right now is a HV Muller 12 twist barrel, my own 85 grain bullets, V133, moving about 3350 -3500 fps.It is great for score where less wind sensitivity and higher bc wins the game over best precision, especially at 200 yds. For lighter conditions, my 30 is more accurate.
For best precision, a light recoiling gun in a real good bag set up, that is very resistant to gun handling mistakes, is what I have learned is best for Group. That means 6PPC with 65-68 gr bullets that run in a moderate velocity, like 3360 fps. I have found that the higher you go with velocity, the harder it is to keep in tune.
If anyone wants more information on the 6.5 br and wants to overcome the obstacles, or try, call me at 989-513-3702.
Other than that, listen to Randy. He has more knowledge and skill with this kind of thing than anyone I know.
My memory just couldn't conjure up the BR case!