First let me say I don’t normally size pellets ( haven’t found productive in increasing accuracy? ) but recently purchased some jsb18.1’s with a head Dia. Of .5.57+ so I decided to try resizing to 5.54-.55 using a old wilson nk. Sizing bushing from an old nk. Die I had from my center fire Days!, using a old beeman pellet sizer... wilson, redding, rcbs bushings fit right in body cavity of sizer almost a perfect fit! By the way used a .218 bushing! Just thought I would pass it on!, plus my RW hp seems to love them sized! First time sizing has actually worked for me...