You usually have to set the ball puller on the sabot and tap it pretty hard to start the screw into the polymer then keep applying downward pressure. Eventually you get it...
Another opportunity..... how about a rod tip attachment that is a screw tip which is .498 at its thickest portion. You'd screw it into the sabot petals then pull it out. Could make one from the tip of a lag bolt if I had a welder.