Certainly cannot speak for PMC brass for the 50 but it is heavy duty and very good for .308s. But that doesn't necessarily equate to how it would be for the big 50. But at least your post got my attention. My son shoots the 50 but he is not immediately available to ask what ammunition he uses.
I thought that Julius carried an XXXVIII, or was it an XLIV, concealed of course so it was not well known.