RCBS neck reamer dies are used in conjunction with RCBS neck reamers in order to remove material from the inside of a case neck that has been downsized with a form die. This step is required when an excess of material has built up in the case neck as a result of neck diameter reduction. The die serves the purpose of preserving the outer dimensions of the case neck during the reaming process. A neck reamer, with the corresponding neck reamer die, is used to remove material from the inside of the neck of a cartridge. This is usually necessary when case forming from another cartridge.
The neck reamer is the "cutting tool" and the neck reamer die holds the case in position.
Neck reamers and neck reamer dies are caliber specific and cannot be used independently, meaning that in any one caliber, both a neck reamer and a neck reamer die must be purchased and then used as a set.
The neck reamer inserts into the top of the neck reamer die.
The neck reamer die is standard 7/8 x 14 thread (unless otherwise noted in the product description) and fit into a standard single stage press.