I buy brass for all my 'good' rifles, sometimes the good brass. Lapua for my 1k rifle, Hirtenberger for my M14.
For the same reason that I buy my powder in larger lots and my bullets and primers in cases from the same lot.
I'd sure be nice if there was a way for you to easily ship me a hockey-sock full of .38 Stupid and 10mm.
"Those who have long enjoyed privileges as we enjoy, forget, in time, that men have died to win them."
Franklin D. Roosvelt