My first shot on elk was a cow running across, left to right. The 300gr. HP cast bullet hit her in the neck just in front of the shoulder
(I led too far & a little high) but it worked very well indeed. Big veins and clipped the spine.
The 2X scope w/post was not a hindrance to the running shot although a higher powered scope might have been. I suspect up to 4X, NP.