Ever worked with one?

I thought not... one glance at Hogdon's website and pressure data tells your QL is nice guess work.

180 GR. HDY SP Hodgdon H4350 .308" 2.820" 56.4 2648 50,700 PSI 60.0C 2826 62,600 PSI

“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery