It's a new Bushnell LRHS so I'm doubtful it's the scope. Maybe it's the mounts. I'm using Talley LW mounts. Bases are tight for sure. Rings are a little tighter than I usually go. Maybe they are too tight??? I'll mount a proven scope with different mounts. If the scope is canted in relation to the bore, would this cause horizontal stringing??
The groups are 5 shots and go about 1.5" horizontal and 1/2"-3/4" vertical.
