Do you have any experience hiking through back country using a Sherman pocket to secure a weapon? It seems like it would be a lot of swaying/movement with nothing securing the bottom of the sherman pocket. What about if you encounter serious brush busting or having to navigate significant obstacles like boulders and/or downed trees, etc.
Is there any concern that the rifle would be unstable in those situations?
As far as the sling keeper goes, my first thought was that I wouldn't want to hike with the barrel in front of my face like that, but with it mounted going the other way, that looks like a much better solution to me.