When a form die is used to reduce the neck diameter of a case, material must be removed from the neck in order to maintain appropriate neck wall thickness. In this case, an RCBS neck reamer will do the trick. This tool will remove the appropriate amount of material from inside the case neck, allowing for easy and proper reloading. Neck reamers must be used in conjunction with a neck reamer die of the appropriate caliber in order to preserve the outside case neck dimensions.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.