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It's not semantics, it's correct. I never suggested using 5.56 in a SAAMI 223 chamber. Critical thinking time: If the longer leade of the 5.56 allows 5.56 spec ammo to use more powder to drive bullets to higher velocities without raising pressures, it follows that using 5.56 ammo in a chamber with a shorter leade will result in higher, possibly dangerous pressures.

Pressure alone does not equal more velocity. A smaller capacity case loaded to the same pressure often results in less velocity because there is less powder, thus less fuel (energy) available to accelerate the bullet

Thank you for proving my point.

We are talking 223 vs 5.56 so the case size is the same. Pressure equals velocity.

I wish people would quit repeating that foolishness; I understand simplifying things for the ignorant but that's oversimplified to the point of being meaningless. Do you get the same velocity from full pressure loads of different powders? Of course not.

Pick'n nits and splitt'n hairs.
You guys are a riot.

I'm a technician. That makes me a professional picker of nits because if I don't get it right the first time, 200 people will suffer a fiery death at 30,000 feet.

TWR, if it were pressure alone, why does a 300 Winchester Magnum need a larger capacity case (combustion chamber) to make more velocity than a 308 Winchester? Why not just increase the powder charge (and thus, pressure) inside the smaller 308 case until 300 WM velocities are achieved? Because it leads to dangerous pressures. For higher velocities, more powder is needed, but the more powder used means case capacity must be increased to keep pressures at a safe level. For the same pressure, the larger capacity of the 300 WM produces more velocity.

Increasing case capacity is just one way to increasing the volume of the combustion chamber. Another is to use longer leade. When the primer ignites, it quickly builds up enough pressure to push the bullet into the rifling which will stop, or, at least slow slow down the bullet's forward motion. That's about where the pressure spikes. This creates additional combustion chamber volume letting the extra powder burn within safe pressure limits. It's a trick Roy Weatherby used back in the fifties to get more oomph out of his cartridges

I am just a follower of directions, 5.56 load data is different than 223 load data. Go to Barnes load data and look up 5.56 and .223.

Western Powders (Accurate, Ramshot) also list both .223 and 5.56 data on their website.