Adam,
I had a Time tuner on my 30br, and was able to speak with the maker personally as he was local for me. I recently sold it to a shooter in VT who is having some very good results on his VFS rig. It does make a difference in your groups.
If you have a chronograph, find the load with the most consistent velocity. Tuner setting does not matter at this point. Once you have found the most consistent velocity, start moving the tuner ONE line at a time. It will seem like such a temptation to move it more, but I promise you you will miss the sweet spot very easily. The "beyond the muzzle" type devices are very sensitive to movement fore and aft in their travel.
The other suggestion I have, and this is only based on my experience with my rifle, is, if this is a centerfire rifle, to have the device expoxied onto the barrel or modify it with some sort of a set screw. The screw clamps just don't give me enough confidence on their own.
Midway through a practice session mine flew off about 20' in front of the bench...the bullet still hit the paper, but it lowered my confidence level for sure. I had it epoxied to the barrel, and then it was much more solid.
