It's not just about matching imprints on the bullet to the barrel. They likely also checked the ammo against what was in the magazine, and I doubt Teran had the

It's not just about matching imprints on the bullet to the barrel. They likely also checked the ammo against what was in the magazine, and I doubt Teran had the same ammo as the police. It might be the same caliber (9mm luger) but there are many different brands of ammunition and bullet types. Atlanta police use Winchester PDX1 147 grain. Most people use lighter hollow points that cost less. Also Atlanta police use Gen 4 Glocks, which have polygonal rifling. Bullets fired from polygonal rifling have very different imprints than those fired from traditional rifling with lands and grooves.