The key individual flaws are as follows:
#1 Both barrels fire at the same time; the two-stage trigger doesn't seem to work. It has some small melted spots on one side.
#2 The barrel does not latch in the firing position, the mating piece on the barrel is chipped / worn. Both barrels seem to fire okay.
#3 The barrel does not latch in the firing position, the mating piece on the barrel is chipped / worn. Both barrels seem to fire okay.
#4 The barrel does not latch in the firing position, the mating piece on the barrel is chipped / worn. Both barrels seem to fire okay.
#5 The barrel does not latch in the firing position, the mating piece on the barrel is chipped / worn. Both barrels seem to fire okay. It has some white grime / residue on it.
#6 The barrel does not latch in the firing position, the mating piece on the barrel is chipped / worn. Both barrels seem to fire okay but they do sound weak. The barrel tip is missing.