John Buckman shoots out the red lantern above the entrance to the whorehouse and it's flame is completely extinguished. However, in a subsequent long shot as the sheriff approaches, the lamp is lit again.
When Post shoots Ben's tin cup, the "bullet hole" has metal shards curling out toward Post. But if Post had indeed fired a bullet at the tin cup, a bullet would have pushed the metal shards towards the inside of the cup. But with the metal shards curling outwards it clearly demonstrates that the so-called bullet hole was created by a small charge placed in the inside of the cup creating the outward curling shards.
John Buckman shoots off 12 shots from a six-shot revolver outside of the whorehouse, with no time to reload.