Harlan was portrayed as a gun expert but
Harlan was portrayed as a gun expert but he didn't know anything about Colt SAA revolvers. When he took the kid to shoot he fired 6 rond from each revolver. That would never happen with a Colt.
A colt SAA holds 6 rounds but it was always loaded with 5. It was unsafe with 6 because the fireing pin would be resting on the primer and if it were bumped or dropped it could go off.