Excessively thick necks can cause high chamber pressures and erratic shooting.
These long snipe reamers will remove excess neck materials to guarantee clearance between the case and chamber - a must if reforming cases from a large caliber to a smaller caliber, such as making 243 Winchester cases from 308 Winchester brass or 25-06 from 30-06.
Reamers are to be used with the Wilson Case Trimmer in place of the trimmer cutter.
Standard reamers are sized for use on fired unsized cases.