Midway sells the slugs. I got a call back from the guy at hasting that developed this he called after my first post .I don't think NEF is inline with this they take the ultra 20 and rechamber it to 3 1/2" now mind you I am pretty much gun spec dumb so this is what I got from what he told me. Some how they change the bbl pressure spec from NEF17,000psi to their 24,000psi
I asked if any competent gunsmith could do the rechamber and he said no now whether that is just marketing ploy or not I do not know but he said that the box to box and different length cases that stay just as accurate has something to do with the way the roll crimp becomes part of the chamber. I think that before I mess this whole thing up I should let one of you guys that know what he may be talking about talk to him and explain it better but sounded good to me but then I've had smoke blown up my you know what before. But ya send your bbl to a company that they have commissioned to do the rechamber $120 shell price is not that bad compared to some other sabot's. Kurt