My range pickups include FC brass with red and sometimes blue/green primer sealant. Are these once fired or another reloader's discards.

Pic's might help but I suspect factory for P D or mil.
I been in this game lots of years,known lots of loaders over the years and none would ever take the time to go to the trouble to seal something that is that tight .
A good rule if the primer ain't tight in the case,toss it.

That confirm my belief. Many thanks.