I knew one guy who had a .280, when I was growing up. His was in the old Model 740. He just used factory loads of the times, of course. (I also only knew one reloader, we almost thought he was Alchemist/Super Gunsmith! ha I don't think they chambered the Remington semi auto in .270 until the Mod 7400/Model Four. I remember you could get the pump in .270 years before that even! Go figure?