I ordered my MGM in 13" tapped for the 6 Hole Base. I sent in both a long seated NOE 360 180 load and a 180 XTP seated in the lower crimp groove with instructions to optomise for both.

Starline making brass for it will make the 357 Maximum single shots a much better choice to own.
Jamerson Brass was too hard a couple years back and would split. My 357 Max Jamerson brass from back in the Summer had no splitting issues, but primer pockets got loose way to soon.

I did a lot of experimentation with 360 Dan Wesson Starline Brass in my 357 Maximum MGM barrel. I was very happy with it, as I have been with all the Starline brass I have bought over the years. No doubt the 357 Maximum Starline brass will be some of the best brass ever made for the 357 Maximum.
I am really glad to see the Starline 357 Maximum brass finally in production.

Bob