Our Swage Rod Backer is made from S-7 tool steel, then through hardened, not case hardened. We've removed the expansion lip, and properly profiled the tip so as to not snag on case necks.
This swage backing rod has a 0.220" stem and is designed specifically for use with 5.56/.223 Shell Cases, but may work with other small primer cases such as 9mm.
Required but not included:
Dillon Swage Backup Die Body p/n 12184
Dillon 9/16x18 Lock nut p/n 13483