S&BBMFF.
Her fingerprints would be on it if so.
There's no mention of any prints on the bullet. If they had Allen's prints on the bullet that would be more direct than going thru the whole gun markings on the bullet. In other words the fingerprints on the bullet would be more than enough to tie him to the scene. They wouldn't need to link the bullet to gun, they would directly link the bullet to Allen.
Again the word "Subjective" in regards to the bullet markings make that piece of evidence questionable. That might be enough to cause reasonable doubt in one juror. It definitely makes me question the bullet.