Was at one of the local combo range-retail stores a couple of days ago. Stopped at the retail side, asked if they had any .300BLK. Staffer said not a bit. Went over to the range to shoot my .22, about 30 feet from retail side. Asked the staffer there if there was any .300BLK. He said, yes, but there was a 3-box (20-rd each) limit, for shooters. S&B 147-gr (and only either that, or the S&B 190-200gr subsonic) for, IIRC, $13.95. This staffer said that, with the limited supply, the manager was allocating ammo disproportionately to the range, since having ammo encouraged more range use.
Still, as they pointed out the obvious, it'd be better to have plenty on both sides of the store.