This is one of those times where a faster bow would suit the job. If you are only using a single pin a faster bow would reduce the drop from that pin, as would lighter arrows, or even arrows with a lower FOC.
To take advantage of the accuracy of a crossbow a multi pinned sight or scope would be a good idea. Crossbow arrows lose speed faster than compounds, so naturally they drop at a quicker rate, it's nice to have a visual of that from a hunters perspective.