I have a couple thousand .223 casings that I got from shooting the Federal "white box" 55gr FMJ loads. I can see that the primers are crimped and with the bullet type that they are likely military ammo. The headstamp is simply "FC", just like any other Federal ammo.

Any experience with this brass?

I'm guessing the best way to see if it the internal capacity is less than typical commercial brass is to weight it.

Ideas?

"The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants." TJ

"All that is necessary for the triumph of evil is for good men to do nothing". EB