Nitestalker is correct, except it lasted from 1979-1981 from what i determined and they went back to calling it the 280 Remington. the 280 Remington and the 7mm Express are the same cartridge, just different names. in 1979, Remington wanted to revive interest in the 280 Rem., so with some clever marketing, they renamed it the 7mm Express. problem was, that people confused it with the 7mm Rem. Mag., so after two years, they went back to using the name 280 Remington.
ballistics wise, the 280 Remington is about in between the 270 Winchester and the 7mm Rem. Mag. a few rifle manufacters do offer it currently.
it is one of my favorites and they are usually scarce to find. i searched for over 10-12 years trying to locate one. i finally found one last year, in an older Ruger M77V (made in 1978) at my LGS. one of my favorite rifles to shoot.