Neck Expander Die Features Everyone who does home reloading would love the RCBS Neck Expander Die-Complete Die. For sizing the neck of a case this expander is an excellent choice. The die is affordably priced made from high-quality steel and comes with a lifetime guarantee from the company. In addition this die comes with a neck sizer with expander/decapping unit that is made to flare the inside dimension of the case neck to just a little more than the actual bullet diameter. With this alignment during the seating process is perfect. Included with the die is a convenient plastic storage case. Neck Expander Die Specifications RCBS Neck Expander Die .284 cal