A lot of variables come into play on this. First off your dad says its "right on". Right on with what kind of load? Did he sight and pattern it for and with turkey loads,did he sight it with slugs, or did he sight it and pattern it with buck shot? It all boils down to what you'll be hunting with,slugs or buckshot. If he sighted it with slugs then use the same brand and gr. of slug he used and the same holds true if he used buckshot to sight it. If you use anything different than what you plan to use then by all means take it to the range and dial it in with what you'll be shooting otherwise you may end up with a wounded or missed deer.