The only difference between the 6700 and the 6700C is the compensator and if I recall correctly, the cost difference is only around $25. When I bought mine, I went ahead and got the C. Shortly there after, I had Kurt at Kurts Kustom make me a new brake to fit on the end in place of the factory compensator. I would post pics, but unfortunatley my PhotoPoint account is dead and I have not gotten a new photo server yet. I also cannot find the pics on my computer or I would send you some. As far as accuracy, I don't believe that there would be any real difference one way or another. Hope this helps somewhat.