.280 Enfield...Ahead of its time

[Tony Williams]

As for the .280 being a better way forward, I have to disagree. It had most of the same undesirable traits as 7.62x51: Rifles heavier and longer than necessary for either infantry or (especially) support troops; ammunition heavier and more powerful than necessary for either infantry or (especially) support troops; limited (20-rd) magazine capacity; excessive muzzle blast in short barrels.

Length of M61 rifle: 38.8 inches: Length of EM-2: 35 inches

Empty weight of M61 rifle: 6.4 lb (iron sights) [M61A2 8.3 lb]: Empty weight of EM-2: 7.5 lb (including optical sight).

The ammunition of the EM-2 was heavier than necessary because of the heavy bullet loading and the selection of the same case diameter as the 7.62mm, but it was not too powerful: muzzle energy was around 1,850 ft/lbs, about the same as the 6.5 Grendel. I am unaware of any problems with muzzle blast (even the short-barrelled Para version had something like a 19 inch barrel).

I will grant you the limited magazine capacity - another result of adopting the 7.62mm case diameter.

If .280 had been adopted by the US, it would've been superseded by 5.56 in the mid-1960s, and for the same reasons 7.62x51 was.

Not unless the US Army insisted on using it in an overweight and oversized rifle like the M14!

The US Army's stated aim for what became the M14 was to replace the M1 Garand, M2 Carbine, M3 SMG and BAR. What they came up with could only replace the Garand, so they scored only 1/4.

The EM-2 and .280 were a complete concept, conceived together. The compact size and light weight of the EM-2 allowed it to be a genuine replacement for the M2 Carbine and SMGs as well as the standard rifle, so it scored 3/4 (in fact, with the optional bipod it arguably would have made the BAR unnecessary too, giving it 4/4).

LRRPF52 has made a strong case that it's a bad idea, and only the Chinese have actually attempted it (with 5.8x42).

The Chinese missed a golden opportunity to introduce a genuine general-purpose cartridge, which was their stated aim. They went with paper ballistics and light ammo/recoil instead of recognising that a round able to replace the 7.62x54R as well as the 7.62x39 must have a far more effective long-range performance.