Bullets and casings exhibit identifiable markings. In regards to the casings there are notable features imparted before and as the casing is ejected from the weapon, including firing pin impressions, breech marks, ejector marks and extractor marks. The bullets will exhibit class characteristics such as lands and grooves, that include number, depth and width, all dependent on the barrel rifling, unique to that firearm. These lands and grooves, cut left or right, cause the bullet to spin as it is fired from the weapon, creating left or right class characteristics visible on the ejected bullet.
There were ten casings discovered at the crime scene but only nine were itemized to be tested, the ones found by Sgt Silva and Dan Horan. It is of high probability that these 9 casings were the ones recovered from the turnout floor and not the casing situated on the front passenger side of the Rambler.
It was essential the casings were ultimately retrieved from the turnout floor, but was the casing inside the Rambler marked on the police sketches then left in situ when the Rambler station wagon was towed away for closer examination, ultimately separating this cartridge from the other nine. Hence the Department of Justice report only highlighting nine casings for testing "Examinations have been conducted of all the bullets and cartridge cases present in items 1 through 8." This means that likely only nine casings were tested, leaving the possibility that the tenth casing found in the front passenger side floorboard of the Rambler was never compared to the other casings. This may be extremely important if we can link this casing to the bullet used in the murder of David Faraday, and identify that the firearm used in this instance was separate to the one used to discharge the other nine bullets, thereby implicating a second weapon and second shooter.
There should have been a further item listed in the Department of Justice report:  'One Super X cartridge case found on the front passenger side of the Rambler station wagon.' But there wasn't.