The Caldwell Lead Sled significantly reduces recoil and provides a great stable rifle rest. The lead sled reduces punishment to your shoulder up to 90% by trapping recoil energy in the frame of the rest. That makes your time at the range more enjoyable and provides for faster, more precise sight-in and load development. The lack of felt recoil while shooting also puts an end to flinching. This prevents development of poor shooting habits that cause problems in the field. Designed for all calibers, and especially effective on medium, large, and magnum caliber rifles and shotgun slugs. The user-friendly portable design includes an adjustable-height front rest and large rubber feet. The lead sled uses Caldwell brand Universal Front Bags (included) for a stable rest and protection of your gun. The lead sled weighs 18 pounds and is designed for use with bags of lead shot (not included). It can be used without any additional lead shot or up to 4 25# bags. (Examples: .30-06 - the lead sled, frame only, reduces recoil 66%; 12 gauge slug - one bag of lead shot reduces recoil 82%; 458 Win Mag - two bags of lead shot reduces recoil 89%.) We stock 25 pound bags of #8 lead shot in our store but due to the weight they are not feasible to ship. Many customers have used home-made sand bags and the Lead Sled does require some assembly.