Yup, they haven't always stocked it, but they have for the last year or so.
Hornady is among the least consistent (I weight sort)
Winchester is nickel plated only now
Nosler and Norma are expensive, but come well prepared (prime, charge, seat bullet - no brass prep required)
Remington brass is relatively consistent and relatively inexpensive.
It's true there is an abundance of .270 and 30-06 brass (cheap!) but I've stuck with headstamped brass for the .280.
Using 30-06 brass is easy though, running through a .280 sizing die forms a false shoulder on that looong neck and its ready to load. The cases come out ~.020" too short overall, but they will still function.
.270 -> .280 is trickier. Seems like instead of sizing the neck to 30 cal and then forming a false shoulder some prefer to seat bullets into the lands (to ensure headspace). 270 win cases are longer, so they'll make the trim length, but either way, you end up fireforming.
At that point, why not call it a 7mm Express, that sounds way cooler than .280AI
