The .280 “controversy” led to all manner of problems decades later.
Along with the new .280 cartridge, the Royal Small Arms Factory design staff had created a revolutionary new rifle, the EM-1 and EM-2 “bullpup” designs. While both cartridge and rifle offered a lot of promise, Prime Minister Churchill wisely saw the need for a united caliber among NATO forces, and rejected the .280 cartridge and the EM rifle program in favor of the 7.62x51 cartridge and an inch-adapted version of the Belgian FN-FAL rifle design (the legendary L1A1 Self-Loading Rifle).
The design staff was very resentful at being rejected, as can be imagined...and about twenty years later, when the development committee for the L1A1’s replacement was formed, the head of the committee was one of the design team veterans of the rejected EM program. And instead of adopting an established design from another country, he decided that, by gum, the new British service rifle would be “an EM rifle”!
After a long series of developmental problems, engineering ineptitude, pirated design details, rigged tests, and suppressed complaints from the end users, the descendant of the EM-2 design replaced the L1A1 as the L85 Individual Weapon (better known as the SA-80). Their first major combat use was during the First Gulf War, and they were a disaster. The German arms firm of Heckler & Koch had to be called in to redesign the rifles and make them, if not ideal, at least more serviceable.
As the debacle of the M-14 rifle program contributed to the closing of Springfield Armory in 1968, likewise the grand scandal of the SA-80 blew up the reputation of RSAF-Enfield and led to its eventual dissolution soon after the SA-80 program was completed.
Try the Czech Vz52 cartridge of the *SHE* rifle, the Czech equivalent of the SKS, a 7,62x45mm, then neck it down for a .280 bullet. Oh, and it's short enough to feed through a .223-cartridge length action, though it REALLY likes the Czech Vz58 AK-lookalike action designed for it, but (mostly) produced in 7,62x39mm M43.