I'm going to be developing a load for 3 different rifles and want to give each one the best opportunity for good groupings. In the past I've used a lead sled, but a couple of guys said that it may open up groups. I've also tried Caldwell shooting bags, but 1 rifle in particular seems to move the crosshairs either to the left or to the left and up when the gun recoils when using the shooting sand bags. I'm wondering if a Caldwell "The Rock" shooting rest would work any better in controlling the recoil. I've tried holding this particular rifle tight and loose, and loose seems to get the better groupings. Anyone have experience with using the shooting bags and "The Rock"? I just found a product called "Bulls Bag". Has anyone used it?