When testing loads, do you let the barrel cool down between each shot or shoot one right after another? I am trying to get my 300 RUM dialed in as good as I can. (I have the sporter barrel) My groups (3 shots) are almost always around 3/4 to 1 1/8 inches no matter what load I shoot. I get the occasional 3 shot 1/2 inch group, but 30 minutes later the group may be 1 1/4. I have not been letting the barrel cool between shots. I was just wondering what the "pros" do. Thanks for your help. I have made a lot of progress in the last 3 months (and spent a trainload of $$$$$)!