.280 Enfield...Ahead of its time

[stanc]

P.O Ackley wrote about the .276's lack of performance in ballistic testing.

I haven't seen that. My info came from Hackley and Woodin, in History of Modern US Military Small Arms Ammunition, Vol. I.

If I remember properly the .276 clips were directional and could only be inserted one way.

That's true of the Pedersen rifle, but the .276 Garand used a clip that could be inserted either way.

I also wonder if the manufacturing technology was ready to produce the AR-10 in large numbers.

Good question. But I doubt that manufacturers would've had any more difficulties than they did trying to produce the M14.