When Winters drops the potato masher in the first 105mm gun's barrel, he doesn't pull the pin out. You can see him pull on it but when the grenade drops into the barrel the pin is still attached.
The C-47s carrying the paratroopers to Normandy are shown taking off in broad daylight; however, in flight they are shown flying in early morning darkness. The flight from England to Normandy was not long enough to account for the amount of time that has elapsed.
At the end of the Brecourt Manor assault, when Winters tells the machine gun teams to fall back, the assistant gunner on the tripod mounted MG holds it by the barrel guard to remove the gun from the mount. In reality, the man would have been severely burned from the accumulated heat after constant firing over the half-hour fight.
The last name of the role played by Andrew Scott --- John D. Hall --- is incorrect. The real person's name is John D. Halls.
The Willys Jeeps on D-Day have wire cutters on the front. This modification was done later, after D-Day.
GIs had a way to get by the reflection rules. They traveled with the windshield down so they could get a shot away without glass in the way, but the Germans figured that out too, so they strung wire across the road at a neck high level. That's why that big wire cutter led the way.
At the end of the episode, 1st Lt. Winters states that PFC John Halls was "not even old enough to buy a beer." The legal drinking age in New York (Halls' home state) in 1944 was 18, which was also the minimum age for conscription in the USA as of 1942. Besides, PFC Halls was 22 years old in June 1944.
A lighter can be seen that doesn't exist at this time. Till 1943, Zippos where made of chrome and had round corners. In 1943, they had to change from chrome to black paint for their standard lighters which were given to soldiers.
In "Day of Days", during the assault on the Brecourt Manor
guns when "Buck" Compton throws a grenade at a fleeing German soldier which appears to explode on impact with him. This is no goof, as Compton (a baseball player at the university) timed the throw so the grenade exploded when close to the German. The grenades had timed fuses, and didn't explode on impact. (See Ambrose, Stephen, "Band of Brothers" page 97.)
A previous post identified an attachment to the M2 .50 cal machine-gun as a blank adapter. In reality, it is am M2HB Flash Supressor. They were not uncommon in cavalry/armor units.
When the soldier that Lt. Winters is with talks about losing his radio and then getting chewed out by his commanding officer. Lt. Winters says: "Well if you were in my platoon, I would say you are a rifleman first and a radioman second." The soldier is in question happens to be carrying a Thompson Submachinegun and not an M1 Garrand or an M1 carbine, but "rifleman" is a generic term for any infantryman regardless of his assigned weapon system. Winters would have made the same statement if the soldier had been carrying a machine gun.
They're in a low flying plane, with an open jump door, smoking cigarettes. Though under those conditions the smoke should immediately dissipate, it doesn't, revealing no air currents in the plane.
In pretty much any shot of the cockpit of the C-47s where the camera is located behind the pilot/copilot with a view of the instrument panel, the gyroscope is stationary in an off center to the left position. This is normal if the panel is not powered and not in use however in the air this would always be on. The line would represent the aircraft's position relative to straight and level flight.
During the scene where Lt. Compton is asking Lt. Winters about the status of their CO, their breath is visible. Since D-Day was in June, this is pretty unlikely.
After the scene where Compton, Toye and Winters storm the second gun, Toye confronts a German solider who attempts to surrender. Numerous angles in this scene show that Toye has lost the stock to his Thompson (likely to have fallen off prior to this scene).
When Speirs comes up during the assault on the German artillery, he hands Winters what is supposed to be a bag full of ammo, which should be quite heavy. The bag clearly weighs almost nothing, as both actors toss it around as if it were a t-shirt.
Before the attack near Brecourt Manor, the staff is studying a local map, on which we can read "Collins Road". In fact the road (and a few others) had been renamed after the 1944 landings, to honor a soldier who died there.
After landing in Normandy and finding some other American paratroopers in the woods, Winters consults a map and declares "We're about seven kilometers away from our objectives." Since the US military did not adopt the metric system until 1957, Winters would have most certainly expressed the distance in miles.
When the C-47s are taking off for D-Day, the pilot in the first airplane is wearing a set of David Clark headsets with their distinctive green earpieces - These were first produced in 1975, and were certainly not available in 1944!.
In the 40th minute, after the their gun is captured, Winters aims his rifle, but the bolt of his M1 is locked back, showing that there is no clip inserted. Therefore, his rifle is out of ammunition.
In the scene where they are taking a gun position at Brecourt, Popeye is hit in the behind with a bullet. As he lunges into the trench, the back of his coat flips up exposing a black wire going across his back with what looks like a red squib attached to the end of it.
Pilot of first C47 on beginning of take-off run can be clearly seen wearing a modern head set with boom mic.
When the American paratrooper discovers that a German POW is really American, he asks where he's from. When the German soldier says he's from Eugene, Oregon, the American declares that he's from Astoria, even naming the street. Since these two cities are over 150 miles apart, in the days before the interstate highway system, it's highly improbable that they would automatically know the details of each other's cities.