The RCBS MatchMaster Duo Set (RCBS part no. 15304) is chambered for 300 Winchester Magnum and pairs RCBS’s MatchMaster precision sizing and seating dies in one matched set. MatchMaster dies are made from case-hardened steel with precision-drilled, reamed, and hand-polished interior surfaces, and the sizing die uses interchangeable neck bushings, sold separately, to precisely set bullet tension while minimizing brass working across firings. The seater die adds RCBS’s micrometer adjustment and exclusive loading window, letting 300 Win Mag reloaders dial seating depth precisely and seat bullets without balancing them on the case mouth by hand.

Key Specifications

• Chambered for 300 Winchester Magnum, matching the die set to this cartridge.
• Pairs a MatchMaster sizing die with a MatchMaster seating die in one set.
• Sizing die uses interchangeable neck bushings, sold separately.
• Seating die features micrometer adjustment and RCBS’s exclusive loading window.

Frequently Asked Questions

What is included in this duo set? A MatchMaster sizing die and a MatchMaster seating die, both chambered for 300 Winchester Magnum.

Do neck bushings come included? No, the sizing die is designed to use interchangeable neck bushings, which are sold separately.

Buy the RCBS MatchMaster Duo Set, 300 Win Mag

Get benchrest-grade precision for your 300 Win Mag loads. Order it from RCBS‘s reloading dies lineup, and our Lubbock, Texas team can help you find compatible neck bushings.