it's another one of those cartridges that remington kept changing the name of also. it was originally called a .280 rem. to compete with the .270. but when the cartridge was developed it was purposely constructed so that a .30/'06 couldn't easily be resized to work, like you can do with a .270, and this really hurt the sales. remington said it was so you wouldn't mis-chamber them and .270's but a lot of handloaders thought it was so they could sell more ammo. then it was renamed the 7mm express. seems like maybe they changed twist rate in the barrell a little, like they did when they changed the name of the .244 rem to 6mm rem. anyway, that didn't help much and eventually they changed it back to the .280 again. it's never had near the popularity that .270 has. a lot of folks that own them say they are far superior to the .270, but the fact of the matter is, it's only .007" (7 thousandths) bigger diameter than a .270 (.277 diameter), and has nearly exactly the same powder capacity. not a bad cartridge by any means. just never caught on like the .270. also, .277 diameter, like the .270 is, is exactly 7mm in diameter. the 7mm is really a little bigger than 7mm's. go figure.