That is correct, records of him buying the gun are not evidence of him using it. I was responding to this part of your comment "So they have a photo of a gun that was "in his possession" but not of him actually _possessing_ [...] Truly damning evidence" There's ample evidence that he possessed the gun, we don't need a photograph of literally everything to reasonably conclude things.
The bullet they found in a cop's stomach matching the gun he owned is evidence that he used it, albeit not unimpeachable proof because matching bullets to guns is a matter you can reasonably question. Nevertheless, I think the sum of the evidence thus-far presented supports the narrative that he shot a cop then the cops turned him into swiss cheese, possibly with the man trying in vane to surrender while that was happening.
OK, he owned a gun, that was found with him, at the time of his death, and his hands were found to have primer residue. Circumstantial evidence is evidence.
