There were a couple of vendors at the last 1500 who had .458 brass, new Starline to be exact. I bought a bag of 50 for $50 or so. I still see Starline showing .458 brass as backordered but I have received email updates from Midway and others notifying me that .458 brass was available. I think it's still in short supply but not as impossible to find as 6 months ago.
If you see some at the upcoming Indy 1500, you should snatch it up before I do!! ;-)
Lol I will be snatching any, brass, rl7,imr4198