We tried to get AZoom (Lyman)to build a batch of them and unless we ordered a huge amount they weren't interested. They weren't even aware that Ruger was chambering the round. Funny how they list 600 and 700 nitros as well as secveral others that are pretty rare but not the 450 thick and thin rims. (BTW Judge, you'll need the thin rimmed for the 450 NE)
I have a set of the Knyoch caps That Chapuisarms has provided a link for. Top notch quality!