I wanted to give an update. Approx 900 rounds through this barrel now.
A couple months ago I was at a practice match and beforehand got down to check my zero, eek I was getting almost 1" groups all of a sudden?! Was it me, what happened to my .3" groups?? A friend said that I should do a seating depth test which I thought was the best idea. Also I had bought a .265" bushing to use which could possibly have changed something, unsure at that point. Oh, and I had ultra sonic cleaned my muzzle brake which was getting kinda nasty.
I was super busy with other shooting disciplines, work, family, health problems, etc, to shoot my 6mmBR much, the next time out which was a month ago my rifle was still shooting the same, just less than 1" groups.
Yesterday morning I finally got to do a fast test with 4 shot groups at 100Y. I tried 5 random depths. Out towards the lands another .012" for the heck of it and progressively into the case with the shortest being .030".
The best group was the .030" into the case which produced low .2-ish wide, .1-ish tall and it was a little windy. The .012" out was next best at .3". The others were .5" to .8".
I chose the .030" into the case because the 105 hybrid at my previous depth was close to the lands and already pretty far up into the neck of the case. (to be specific, if I chase the lands there isn't going to be much of the bearing surface of the bullet left in the neck after a while)
Glad my 6mmBR still shoots well!