Re: AAC 7.62-SDN-6 Accuracy
Mine should clear any time now, so I can't address it with any detail.
However, I had an 18tooth 762SD before this one, and it tightened the groups on my 20 inch barrel Rem 5R .308 by 1/8 to 1/4 of an inch. It worked admirably, and never loosened during use. A buddy has another 18tooth 762SD that he uses on his Larue OBR with no problems.
I anticipate that the N6 will work just as well. The only variable is the 51 tooth mount can allow a little slop if you get just the wrong mount/can combo. The cure for that is to get your dealer to allow you to test several mounts and select one that is perfect for your can - latches just at the point when the mating surfaces meet. I tested the .30 cal brake mount that I have with my can (still at the dealer) and it couldn't be a better match. The 5.56 brake mount that I have allowed a little slop, so I'm going to either root through his pile of mounts and pick a better match OR polish the mating surface on my mount until I catch another tooth.
The vast majority of folks who own an N6 will tell you that the "mount slop" issue hasn't been a problem for them. If you encounter it (and you care/it matters to you) then it is fixable by "tuning" your mount or selecting a better matched mount.
Aside from that issue (non-issue?) I am confident that the N6 is going to be an excellent multi-cal can for precision and bullet-hoses alike.