What is better than one BART tool? Both AR 10 and AR 15 BART tools for one low price. Whether you are a professional armorer, gunsmith, or hobbyist, if you work on AR's you cannot afford to be without this set of tools. One FREE .5 oz bottle of x-caliber lapping compound included. AR-10 weighs 43 OZ. AR-15 weighs 30 OZ.