I know this is an old thread, but maybe someone would like to know my results. Been shooting bertram .300 WSM for a little while now. I got 100 pieces from grafs which was (5) 20 round baggies. I assumed it was quality stuff and by mixing it would be alright. I loaded them up with a generic load to fire form them and break in my barrel. I sized (redding type s FL bumping the shoulder .002" with a bushing about .002 smaller than a loaded round, expanded (Sinclair expander die and carbide expander), then trimmed. I loaded them up and there was a stupid amount of difference with seating pressure between the casings and extreme velocity spreads sure showed. I'm trying to get away with not turning necks on this hunting rifle. I annealed the necks for the second loading and it was way more consistent pressure seating and es's went waaaaay down. All is well until my 4th loading and same type of inconsistent tension while seating. I annealed again and on the 5th loading, seating pressure was pretty consistent as well as velocities.
Not saying anything bad about the brass, because it did come in 5 different "lots", but I find it odd that I can't ever really keep things consistent. Even when sizing, its being sized the very minimum amount and it just feels like its tough shit and doesn't want to mold.
Anyway, take it or leave it, that's what Ive found so far. When this stuff is shot up, I'm going back to norma for WSM. Ill take consistency over toughness for what I'm doing with it.