The RCBS Hand Case Neck Turner is designed to peel brass from the outside of a case neck to a consistent thickness which is important because most commercially available brass has variances in neck thickness. This leads to case neck concentricity and bullet run-out issues. Truing up the case neck produces more consistent and accurate hand loaded ammunition. The cutter portion uses caliber specific pilot/mandrels (sold separately) to guide the case neck. The cutter design can zero the cutter to the pilot/mandrel and then use the micrometer adjustment to dial the desired case neck thickness in .0005-inch increments. The cutter can also be set for right or left handed use. – Caliber specific pilot/mandrels (sold separately) guide the case neck – Cutter design can zero the cutter to the pilot/mandrel and then use the micrometer adjustment to dial the desired case neck thickness in .0005-inch increments – Right- or left-handed use.