How hot is it, and how long between shots? Over 60F take 5min or more between firing and beginning to load to guarantee the heat isn't ruining your groups.

As for the 200gr SWs blowing apart in deer with over 100gr of powder, frankly whoever told you that is full of BS or has never even tried them. I've shot them exclusively pretty much since they were introduced, taking dozens of deer, and I can count on one hand the number that did not exit.