When Silver shows off his shooting skills he is using a Colt .45 Peacemaker, a single action revolver that requires the hammer be pulled back manually before firing each round.
Doing this one handed as Silver would have had to do is difficult enough for an adult, for a kid Silvers age it would be impossible, his hands are neither big nor muscular enough, you can clearly see his thumb remains closed around the gun throughout the whole scene.
Also light can be seen though the chamber as the camera looks directly down the barrel, there's no way that could happen with a fully loaded gun, the continuity people didn't even bother to blank off where the cartridges should be.