The .270 (a relic from 1925) was already well planted when the .280 came out.....I seriously doubt that the buying public was going to be swayed from the well entrenched .270.....it's use in American (and other places) big game hunting well documented.....

Had Remington loaded the .280 to the same pressures as the .270, it might have done better but instead got somewhat of a reputation as a handloading proposition. For a lot of folks this wasn't in their environment.

Instead of asking why the .280 did so poorly, one might ask why the .270 sold so well.....because in fact it really didn't do anything the .30-06 didn't do!!!!.....and the .30-06 ammo was available in military surplus all over the place in the '60s!

The .270 got a reputation as a flatter shooting round.....anyone want to say just how much flatter than the .30-06?.....it's not much I can assure you!

For those that KNOW why one succeeded and another failed....let me say this.....you're guessing just the same as I and everyone else!