Character mistake: When Melanie and Scarlett are talking with an (off-screen) wounded Confederate soldier, the soldier says he hasn't heard from his brother since Bull Run. Only Northerners refer to that battle as Bull Run; Southerners have always referred to it as Manassas.
Character mistake: Following the barricade recovery of the Corsair, the Officer of the Deck instructs the helmsman to return to course "three five oh." No line officer would use the term "oh" in place of "zero", especially when giving course change instructions.
Character mistake: On the way approaching town the camera pans to a woman's hanged body with a sign written in German around her neck. One of the crew asked Wardaddy what it said, to which he answered something like "It reads 'I am a coward who refused to fight for the German people'." That sign actually translates to "I wanted my children not to go fight" or Anglicized for better effect, "I refused to let my children to go to war." Interestingly, once into town, there appears the corpse of a hanged man with a sign written in German that does translate to what Wardaddy said of the first sign. (00:43:00)
Character mistake: After accurately depth charging U-571, the German destroyer crew suddenly turns out to be almost comically and unrealistically incompetent at the end of the movie. Not only do they barely hit U-571 with their guns, but they also can't keep up with the sub. But even with both submarine diesel engines running flank speed (of which U-571 only has one badly damaged engine operational), a common WWII destroyer would easily be twice as fast as a Type VII U-boat. The destroyer could swiftly close the distance and could either ram U-571 or cross the sub's wake to bring all its weapons to bear and make it more difficult to get hit by the sub. Of course the destroyer doesn't do that but stays perfectly in U-571's wake for an easy kill shot from its stern tube. In reality, it was considered an incredible feat to sink a destroyer with a torpedo, since they were agile at full speed, could easily dodge torpedoes and had shallow draft. This destroyer crew however, seems actively trying to get killed.
Character mistake: In the courtyard of the castle there is an anti-aircraft gun. You could probably not find a worse place for a gun like that even if you tried (except maybe if you put it inside, in a windowless room). In the position it is placed it can only fire at targets directly above the castle. What you want to do is fire at targets before they reach the castle. It would be better if they placed it on the roof, or even near the village below.
Character mistake: When Maximus is talking to Marcus Aerelius, he mentions that his wife has black hair. But in the scenes where we see her, she actually has brown hair. (00:24:40)
Character mistake: In a conference with Crockett and Bowie, Travis states that Fannin in Goliad is preparing to relieve the Alamo and will be ready to "march south by the end of the week." Goliad is 90 miles south of San Antonio. To relieve the Alamo, Fannin would need to march north.
Character mistake: When the Marines are navigating through the Paris Island obstacle course, Hartman is shouting "It should take you no less than 10 seconds to negotiate this obstacle!" In other words, the LONGER it takes someone to get across, the better? (00:13:27)
Character mistake: Before they jump off the plane Halloran should at least have checked if Sellinger has his parachute strapped on properly, knowing that the other guy has absolutely no experience. (01:05:55)
Character mistake: Hicox salutes General Fenech, who returns the salute. But Fenech is bareheaded and therefore under British military protocol cannot salute. He would instead acknowledge the salute with a nod.
Character mistake: After Captain Willard walks through the front door of the burnt out French plantation dock there's a close-up of Chief Phillips at the wheel the boat. He turns around and looks right at Chef and says, "Lance". (01:56:40)
Character mistake: When Chris joins the Marine unit they are going to breach a door. Chris removes his shooting hand from his weapon to signal the breacher. He would have used his support hand.
Character mistake: When Doug Masters approaches his aircraft at the airfield before racing 'The Snake', Col Sinclair has a right hand access panel open on Doug's Cessna 150 upper engine cowling and is allegedly working on the fuel system saying "As lean as you were runnin', if it went into a stall, you woulda lost your engine, and would never been able to pull it out." The carburetor, gascolator, throttle linkage and carburetor control lines are on the bottom of the engine (Continental O-200). The panel he closes after sticking bubble gum on accesses the battery, the right hand magneto and the oil dipstick. Not only did Col Sinclair not do what he said he said he did without a sign-off in the aircraft's logbook, it would be totally unnecessary, as aviation updraft carburetors use a cockpit or engine controlled fuel mixture control that would have simply been left in 'full rich' position after engine start for the altitudes the aircraft would have been flying. And stalling is an aerodynamic condition of angle of attack being exceeded or insufficient airflow over flight surfaces, not fuel starvation, which is the condition being addressed. (00:11:30 - 00:12:30)
Character mistake: About half-way into the movie the Captain asks for a fathometer reading and is told 150 fathoms. He preforms a mental calculation and says that it is 310 meters and over a thousand feet. In fact, 150 fathoms is 275 meters or 900 feet (1 fathom = 6 feet = 1.83 meters). (00:57:15 - 00:57:40)
Character mistake: When the Japanese attack is imminent, a soldier loads the 50 caliber machine gun rounds into the box backwards, with the rounds facing the gunner.
Character mistake: When Barry Lyndon is talking to his mother privately, while standing on the bridge overlooking the water, Barry's mother refers to Barry's son Brian as being "at the mercy of his stepbrother", meaning Lord Bullingdon. They have the same mother. Lord Bullingdon and Brian would be half brothers, not step brothers.
Character mistake: The closing shot of a newspaper article shows the word "rumor", film is set in England where it's spelled "rumour".
Character mistake: When the deputies chase Rambo in the forest, sometimes Teasle refers to Shingleton as Shingleton, but sometimes he calls him Singleton.
Character mistake: In the scene where Crapgame is sitting in the back of the truck at the end, when the men are loading Kelly's squad's take after splitting with the Germans and Oddball, Crapgame asks Fisher to verify his calculations. There are 125 boxes of gold left valued at $8,400 per box. Fisher says that they are worth $10.5 million, and each of the twelve men in the squad will get $875,000. The actual amount (125 x 8400) is $1.05 million, making a per man take of $87,500. He's off by a factor of 10 one way or another.
Character mistake: Before the final attack in the village, we can see a wall with an advertising for Byrrh, an aperitif drink made from a blend of wines. The ad reads: "Byrrh, l'ami de l'estomach, " which basically means: "Byrrh, stomach's friend." In French, the correct spelling is "estomac." not "estomach." This is quite a big mistake since the ad and the building are three or four stories high.