I have had two 6/250's, customs for shooting chucks and P. dogs.
60's at 3900, 70's at 3550 were very accurate and the only powder I ever used was WC844 which is H335.
If you are considering going this route, then you may consider the 6/250 AI, which will get you another 200+ fps at a minimum, and is a very accurate cartridge, I shot the barrel out of two of these also.
Both of these cartridges will feed from the magazine fine.
The 6/250 AI is right on the heels of the 243AI with less powder.
With either cartridge, you will be happy, make no mistake about that fact, however you will not have quite the accuracy of the 6 BR.
Your choice of the 6/250 over the 6 BR is a good one due to the cost of brass...exactly my thinking as my 6br's were finicky to feed out of the magazine plus the fact that the brass was lost while in the field shooting coyotes.
Pac Nor Super match barrels are what I used on these 4 barrels. I sent them dummy rounds with the bullet seated the way I wanted it and they matched it perfectly with no extra charge. I used - twists on both cartridges.
Good Luck
