Star Pusher Punch

[RAC]

Hi Veral.  I am quoting from your brochure:  

"To take advantage of the Stars potential with gas checked bullets, the pusher punch must be fairly close to sizer diameter, having about .010 to .015 undersize. Then its end needs to be cupped out a few thousandths so only about a 1/32 inch wide contact ring is left around the perimeter. This so all pressure is applied around the outer edge of the GC base, straddling any raised sprue etc."

How do I go about  cupping the Star Pusher Punch?  Thanks.
Roger

[nathan]

What I did was take it to a machinist (father-in-law), and had him take some material out of the middle of the punch's face surface.  The final product was a punch that only put force on the outside edge of the gas check as it was seated.  Hope this helps..ns

[Veral]

Nathan gave a very good explaination.  It must be done in a lathe to insure the precision required.  Use this type punch with gas checked bullets only, in the Star sizer.  Do the same with the lift out plug for in and out sizers like the  RCBS and Lyman, and apply enough pressure at the bottom of the sizing stroke to imprint a tiny ring at least 75% of the way around the bullet base..

   A dramatic account of what results can be:  I had a 240 gr cast plain base load for a 44 magnum Marlin which printed around 1 3/4 inch at 50 yards.  After bump squaring the bases, no other changes to the load, all bullets went through a ragged hole, group well under a half inch.  ------  Understand that results are most dramatic with short for the caliber bullets like this, but it will show clearly on target with any bullet/load/caliber.