"... thats like saying 38 and 357 are the same..."

Nope. Those are different calibers. But, a .357 revolver can shoot .38 specials. I have one that does that.

What you've been doing is mixing calibers and millimeter bullet measurements.

5.56mm and .223 caliber ammo can both be used in ARs.

Just like .308 caliber and 7.62×51mm NATO can be used in the same rifles.

You are the one who has no idea what you're talking about, and instead of acknowledging it, you repeatedly keep doubling-down.

"... thats like saying 38 and 357 are the same..."

Nope. Those are different calibers. But, a .357 revolver can shot .38 specials. I have one that does that.

What you've been doing is mixing calibers and millimeter bullet measurements.

5.56mm and .223 caliber bullets can both be used in ARs.

Just like .308 caliber and 7.62×51mm NATO can be used in the same rifles.

You are the one who has know idea what you're talking about, and instead of acknowledging it, you repeatedly keep doubling-down.