Virgin Brass
Unfired new cartridge cases, which usually benefit from a light prep pass and may need one firing to settle into the chamber.
Virgin brass is factory-new, never-fired brass bought specifically for reloading rather than salvaged from spent ammunition. It arrives clean and uniform in headstamp, which is why precision handloaders often prefer it as a known starting point over mixed once-fired-brass. New cases still vary slightly from the box, so a light prep pass is common practice.
That prep typically includes uniforming the case mouths, deburring and chamfering, and sometimes neck sizing or trimming to a consistent length before the first load. Because the cases have not yet taken the shape of the rifle’s chamber, the first firing acts as fireforming, after which the brass settles in and tends to deliver its most consistent results.