The weather during the Minnesota robbery changes dramatically between shots.
During the Northfield bank robbery, when the bank customer is shot running out the door to warn the town, he is shot in the back and blood splatters on the glass of the door. In subsequent shots of the door the blood splatter disappears.
When Bob Younger is thrown from his horse in Northfield, Minnesota, and in the next two shots of him as he struggles to his feet under fire, he is holding a revolver in each hand. When the shot next cuts to him, he is frantically working and firing a Winchester 1866 (Yellow-boy) rifle. Presumably this came from the boot in his horse's saddle, but he has had barely a second in which to retrieve it.
Belle fires her Derringer pistol and breaks a glass at the bar but the mirror behind it doesn't even crack.
During the Northfield bank robbery, a bank customer is shot running out the door to warn the town, and falls in the street with his suit jacket bunched up towards his head. In subsequent shots, his suit jacket is all the way down.
The revolver Frank James threatens Rixley with and carries throughout the movie is a Smith-Wesson Schofield. In reality, Jesse carried a pair of Schofields while Frank preferred the heavier Remington New Army (the type of pistol shown carried by Cole Younger). After leaving prison, Frank James did a print testimonial for Remington referring to the Remington as 'the finest hand gun I ever carried'.
When the reporter interviews Zerelda at McCorkindale's funeral she tells him that her 2nd husband was Ruben Samuel. He was her third husband. Her second husband was named Benjamin Simms.
John Younger was actually Jim Younger's brother, not his cousin. Also, he was 23 when he was shot by the Pinkertons, not 18. And though it's not known whether he took part in any robberies, he had been a member of the James-Younger gang.
Despite Rixley claiming that Minnesota "doesn't allow hanging", the State actually had the death penalty between 1860-1906
What appear to be modern-day power lines are visible in the scenes shot in Georgia; however, these could be telegraph lines.
During the Northfield raid, when the steam engine came up the street, the tracks from the flat wheels and the heavy weight could be clearly seen in the dirt of the street, but on the next scene as the riders were coming up the street, there were no tracks visible.
As Cole Younger takes a gun shot hit while on his horse in Northfield, duct tape from the special effects team is clearly visible on his shirt as his duster flies back.
During the knife fight, the position of Sam Starr's holster and knife switches from left to right during a brief shot while Cole's knife is switched to his left hand indicating that the shot was mirrored.
During the dance a Confederate flag is hanging from a beam. It is the traditional Southern Cross flag. But it is the Confederate Naval Jack (which is rectangular in shape) and not the Confederate Battle Flag (which is square in shape). For the rural hill people of western Missouri to have a Naval Jack is highly unlikely. If these people had a Confederate flag, it would have been the Battle Flag, the Stars and Bars, or any number of other Confederate flags used in land battles (particularly those in the Missouri Theatre), and NOT the Naval Jack.
The song "I'm a Good Ole Rebel", sung in the saloon scene, was not written until 1918.
The guitarist in the bordello is asked to sing "I'm a good ole rebel". The song was only copyrighted in 1915. Although it is possible that it was known in the period portrayed (early 1870s), it is unlikely that it would be so widely known that the performer would have been able to play it from memory. If so, it would raise the question why the author had not copyrighted.
Electric lights used throughout, especially at Jesse James' house and on the train he and his gang rode to Minnesota.
In some of the shots where there are horses pulling a wagon, it is clear that the trails they are on were made by modern vehicles. Clearly if they were wagon trails, the wheel lanes would be smaller and the center of the trail would be torn and scattered from horse's hooves.
The Texas flag at the saloon Cole visits is made out of Nylon, which wasn't invented until 1935.
When the wagon trains and horses are shown riding down the street in Northfield, Minnesota before the bank robbery, the clacking of horses' hooves can be heard (the sound they make when walking on pavement or concrete) even though they're walking on dirt.
When making their escape after Northfield Bank robbery, a rider slams into a tree limb. The cable used to snap the actor back off his horse is visible.
During the train robbery, when Jesse kicks open the door to the passenger car, shot from inside, a stage light is clearly visible behind him (above his right shoulder).
Chapter 13; 1:18:49 Northfield shootout (again), car parked behind green wagon. (Prior to horses jumping through glass windows.)
Cole Younger (David Carradine) is shot in the right leg and arm while riding his horse in Northfield, As each squib is activated, the button in his right hand used to fire the squib is visible. The wire leading from the button up his sleeve can be seen when he is shot in the arm along with gaffer's tape on his shirt to hold something in place.
When the brothers are making their escape after Northfield Bank robbery, Cole Younger (David Carradine) is shot in the leg. You can see the detonator for the detonator in his right hand and the wire going down his sleeve (1:39:40).
In the scene when Ed Miller is kicked out of the gang, the characters are gathered on what appears to be a narrow beach, with no 'far' river bank visible. Missouri has no coastline.
At the end of the knife fight Cole Younger takes Sam Starr's knife and puts it in his sheath, leaving his own knife stuck in Sam's leg.