As some of you are aware, the LaRue 7.62 OBR has rapidly become a viable option for many professional shooters in lieu of the more traditional bolt gun. The 16" barrel has superb accuracy, reliability and easy maneuverability, which make for a very attractive package.
However, just like a bolt gun, the semi-auto is subject to POI shifts when a suppressor is introduced into the equation. Having to anticipate, or compensate for that shift under stress is not always easy.
Here is how Gemtech worked with me to minimize the POI shift and increase the repeatability of the OBR/suppressor combination. First of all, the bi-lock QD insures that the suppressor goes on the same each and every time. Secondly, the mount places the distal end 2.35" of barrel in tension to help offset the various stress factors caused by the suppressor. The last, and potentially, most important factor is the use of a titanium suppressor, which minimizes the weight hanging off the end of the barrel.
Here is a drawing showing how the barrel is profiled to accept the tensioning QD mount.
The QD installed
And the results; the initial group (left and center) works out to a .382 MOA, and was shot without the suppressor. The second group (3 shot vertical string low to the right) was shot with the suppressor and opens the total group up to just 1.152 MOA. I'm a very happy camper!