Only if the bullet is intact.
Only if the barrel/chamber has not been modified through months or years of use.
Only if the barrel/chamber has not been replaced.
Only if the barrel/chamber has not be intentionally modified.
Only if the bullet has not been intentionally modified prior to firing.
Only if the ammunition has not changed substantially.
Only if normal bullets are used, and not discarding sabot bullets.
Fingerprint makes it sound as if its unique, just like DNA. Its possible for multiple barrels to impart the same markings on bullets.