I have been thinking about getting rid of my solid rest and going with one of those shooting bags, I see several different ones on the market. Bulls bags Dog-gone-good stoney point caldwell shooting products I would think a person would want the heaviest bag he could get so it didn't move or moved as little as possible. Also should a person get one pre-filled with that regrind stuff???? or buy a bag of lead shot??? I would think the lead shot is heavier. Anybody out there using any of these products????