I have 6mmBR, 243Win, and 6mmRem reamers and have built rifles for myself.
I have a 243AI that someone else built.
The latest was in in Sept 2016 I built a lightweight rifle in 6mmBR.
The nice thing about 6mmBR is the tiny groups either Rem or Lapua brass.
October 2016
6mmBR 95 gr Nos Bal Tip moly 29 gr IMR-4166 2800 fps chrono 27" Pac Nor super match 8" twist barrel