For the American reloader dedicated to achieving the pinnacle of accuracy from the classic and superbly balanced .257 Roberts, the Lee Precision Collet 2-Die Set is the ultimate tool for crafting true match-grade ammunition. This innovative set, which includes the Collet Neck Sizing Die, Dead Length Bullet Seating Die, a shell holder, and a powder dipper, is engineered to produce rounds perfectly customized to your rifle. The genius of the collet die is that it only sizes the case neck, leaving the body perfectly fire-formed to your specific chamber; this custom fit is a well-known secret to achieving incredible accuracy. By minimally working the brass without the need for lubrication, this die also dramatically extends the life of your cases, making it a wise investment for any precision-minded shooter. Please note, this die set is designed to create the most accurate ammunition possible for bolt-action rifles and is not recommended for semi-automatic or lever-action firearms.