The CCI41 is a commonly recommended primer for the 6.8, which is a hard cup mil-spec magnum primer. So naturally, the non-mil-spec, lighter hammer fall counterpart would be the 450. Hornady calls for 41's, I had a buttload of 450's, so that's what I used with their charge data. No problems, and no early pressure signs at max or near max loads.

I use both mag and standards for 6.8, just depending on what the book calls for. I seldom haven't found a suitable load in a book, so I don't often feel compelled to pioneer off map.

Then again, Nosler's book calls for a Rem 9 1/2 in all of the listed 6.8SPC loads, so I'm still trying to figure out how to make that one work... I've assumed it was a typo and used 7 1/2's, worked just fine.