Forster Neck Reamer #220 For Original Classic And Power Case Trimmers. .220 Actual Diameter.. 224 .243 .264 .284 .308 .429 and many others. When reloading if the case neck is too thick it can put pressure on the chamber and cause flyers. By mounting this neck reamer in the Case Trimmer rather than the pilot it helps eliminate excess brass from the walls of the neck. This particular neck reamer grinds the entire bullet diameter to precision creating perfect symmetry. Made from strong and durable steel the reamer is designed for unsized and untrimmed fired cases. Specifications for Forster Neck Reamer: Manufacturer: Forster Quantity: 1 Color: Silver Package Contents: Forster Neck Reamer Forster NR1220: Neck Reamer #220 For Original Classic And Power Case Trimmers. .220 Actual Diameter.