This Ram Prime is made to specific dimensions for the 50 BMG. Perfect for the Lee Classic Cast Press. Shellholder Used: Lee 50 BMG Shellholder. Other manufacturer's shellholders priming holes may be to small for the diameter of the ram prime.Notes: Includes punch for 50 BMG Primers. Ram Prime works on press upstroke rather than downstroke for increased leverage and positive primer seating feel. This is the same unit that is included with the Lee 50 BMG Classic Cast Press Kit.