If your rifle is bedded well and free floated, you are going to have a pretty significant barrel harmonic caused by the recoil impulse in the Y-axis. I'm imagining a springboard here. Depending on where your bullet comes out of the muzzle, you are going to see vertical change, with the barrel harmonic being in the vertical axis.
I wouldn't want to try this, but shoot the rifle sideways and see what happens. If you survive, tell us what happens.
This is a high-speed video of a 50 BMG. It has a totally different action (plus a lower center of recoil with less rotational effect) but seems to illustrate what I am thinking. Watch the scope flex (Y-axis) and then at the very end, watch the barrel do the same.