Well he had a revolver as well. We don’t which weapon was used.
This is Wictor’s theory.
It has some validity, as we now know the security card did not stop Paddock, nor did the first officers on the scene.
And he stopped firing a full 60 minutes before his suite door was breached.
The big question is why did he stop firing with 23 guns and much more ammo to expend.
Oh, I agree that is the big question. But the answer offered in the case, IMO, is less than compelling.