I mostly use sand filled leather bags. I also have the large size "Bulls Bag" but have not used it as much since while it does squeeze the forearm and hold the rifle steady, I find that I'm always fighting it to adjust the crosshairs a bit before a shot. I also have a Caldwell Rock but since I find myself shooting off the hood of my truck at various places on the farm, the little pointed feet on the Rock aren't acceptable even on my truck as rough as the paint job is. One comment about The Rock is that mine was definitely a mistake that got past the Quality inspector. One of the threaded holes for the pointed feet had half the threads drilled out with an oversized drill. Also the main shaft holding the rest is either bent or the top machined surface of the base is not perpendicular to the centerline of the hole because when you turn the shaft to adjust the rest height, it will make you drunk to watch it dancing around like a hula dancer. Once adjusted it's as steady as if these problems didn't exist so I just use it "as-is" when I do use it. Not sure how many Caldwell let out like this one as I've never heard of anybody else getting one like this.