.280 Enfield...Ahead of its time

[stanc]

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...

True, but the pertinent fact is that it was heavier and bulkier than necessary.

I am unaware of any problems with muzzle blast (even the short-barrelled Para version had something like a 19 inch barrel).

In line with the thread title, I was thinking of the 10.5-inch and 14.5-inch barrels currently in US service. I'm sure muzzle blast in 19-inch and longer barrels was tolerable.

If .280 had been adopted by the US, it would've been superseded by 5.56 in the mid-1960s, and for the same reasons 7.62x51 was.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

And that's precisely what they would have done.

Like the British, the Americans wanted to have a rifle of their own design. To this day, the US Army has disliked bullpup rifles, which ruled out adoption of the EM-2, and they clearly weren't ready to accept the AR-10.

That leaves the T44/M14, and I think it very unlikely they'd have gone to the trouble and expense of redesigning the receiver to optimize it for a 0.25" shorter cartridge. They may have cut the barrel to 20-inch length (as in the T44E6, below) for a .280 M14, but that would've produced negligible weight reduction.

So, with a .280 M14 they still would've encountered the same manufacturing delays that led to the forced adoption of the M16 and 5.56x45 ammunition.

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.

Agreed. However, that situation wouldn't have been any different with a .280 M14.

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).

I think you may be a tad optimistic about that. But, even if you're right, it's irrelevant because the US Army would never have adopted the EM-2.

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.

I completely agree.