Actually, I haven't seen anything on why not to make major with universal.
I've since loaded up 170pf loads with universal, titegroup, and powerpistol. The Universal loads at 4.7 grains were virtually indistinguishable from the titegroup loads in any qualitative sense and 3/10ths under the starting load of 5.0 grains that Hodgson publishes. The load that blew up was only 0.12 grains over hodgson's published max. Of course the Bear Creeks are not exactly equivalent to the XTP hodgson published data for.
I believe you mean Clays not Universal Clays.
Clays has a faster burn rate than Universal Clays.
Search the web site for other references guys !