The sniper rifle used in the church bell tower is a Russian made Mosin Nagant 91/30 with a 3.5X power side mounted telescope, which is correct for the rifle and time period. However, the rifle fires Russian ammunition, in a caliber unique to the Russian military, which would not have been available to U.S. soldiers in WWII. The 91/30 sniper rifles were however imported in great quantity after World War II by many U.S. importers, and would have been readily available to serve as props in movie making. New England Firearms and Remington Arms, both U.S. companies, fulfilled U.S. contracts to produce approximately 2.8 Million 91/30 rifles after WWI. Both Remington and Winchester produced ammunition for these rifles. While it is highly unlikely that a U.S. soldier would use a 91/30, it was possible. However, no U.S. company made any PU scopes. The acquisition of some of these rifles was possible by U.S. troops in the ETO at the time.
Following the retreat from the barn / death of the German Colonel, while the men are resting alongside the convoy, Stuart Margolin's jeep is followed by a Willys M-38 Jeep which wasn't produced until 1950.
The 50cal MG on the half-track changes throughout the film. It's shown at some points to have a perforated barrel jacket (like on an M1919A4 30Cal), and then at other times seen to have a normal barrel
When Kelly, Big Joe, Oddball, and the German Tank Commander enter through the blown up bank door, the other soldiers pour in from adjoining rooms. The front door was supposedly the only entrance into the bank and one of the reasons for enlisting the help of the German Tank Commander.
When the soldiers are leaving the mine field, one is carrying a .30 Cal machine gun on his shoulder. The end of the barrel is smooth and has a very small hole, indicating it is a Blank Firing Adaptor, used to fire blank rounds. A minute later, Don Rickles exits the mine field, also carrying a .30 Cal. The barrel bushing in this case has a much larger hole and a vertical slot used for disassembling the weapon. This would be the correct bushing for firing live ammo.
When Kelly pulls back the canvas to reveal the boxes of gold in the bank, a large shard of glass lands on top of one of the boxes. A moment later he lifts the box up in order to drop it, but the shard is gone.
Early in the film, Kelly is sitting by the side of the road in a jeep telling Big Joe of his plans to get the gold. In the background, a column of German POWs files past. The camera switches to a reverse angle and instead of German POWs in the background we now see a band of refugees.
when Kelly is interrogating the German Colonel at the beginning of the movie, he gets a bottle of brandy from Little Joe, it is square with a short neck. He walks around the Jeep and places the bottle down on a table and it has become round with a longer neck.
When Kelly first drives his jeep into the compound to meet Crapgame, the camera is pointing to the back of the jeep as it enters. At that point the machine gun mounted at the back is pointed roughly 45 degrees up. In the next shot, the camera is pointing at the front of the jeep and the machine gun is only pointing maybe 20 degrees up.
When Kelly is exiting his jeep to go visit Mulligan he brings along a bottle of whiskey. Later when he goes to visit Crapgame he is given a bottle of whiskey and is seen taking it with him after he leaves. This indicates the Mulligan scene was originally supposed to be placed after the Crapgame scene but was switched for some reason.
Early in the film, Kelly is sitting by the side of the road in a jeep telling Big Joe of his plans to get the gold. In the background, a column of German POWs files past. The camera switches to a reverse angle and instead of German POWs in the background we now see a band of refugees - but who is the guy at the back of Kelly's Jeep wearing a striped button down and tee shirt?
When the Tiger is shooting up the city at the end there is a clear gap in time between the sound of the cannon and the actual explosion. At that distance of next to nothing it would have been almost simultaneous.
The sniper rifle used by Pvt Gutowski in the bell tower is a Moisin Nagant 91/30, with the correct PU scope. During several scenes, the view is featured through the scope, showing a graduated full crosshair reticle. PU scopes actually featured a heavy, three-post reticle.
Collars and collar patches of Waffen SS Panzer troops officer's uniforms were piped with silver braid as is correctly shown for two of the Germans. The sergeant commanding the tank at the end however is incorrectly shown as having white piping. Only German Army Panzer troops ever had full piping for all ranks and this was normally rose pink (the arm-of-service colour for the panzer-troops). It could also be gold (armoured cavalry) or black/white stripes (panzer pioneers), but never white. And only collar patches were piped after 1943 (officially). Some Waffen-SS panzer troops wore pink piped collar patches late in the war to be closer to the army style, but SS panzer uniforms never had the full pink piping of the early war army ones.
When General Colt asks his aide for the aerial photographs, his aide is wearing three stars on his lapel insignia. Since General Colt is a Major General his aide should be wearing lapels with two stars on each insignia.
When the German column approaches the ambush at the mine field, the convoy commander is riding in the front seat of the command car. German officers always rode in the back seat of their vehicles, and the front seat was only used by the lowest ranking officer if the car was full.
Odd-ball mentions that his Sherman tank has an "ordinary 76mm" gun. The Shermans in the movie are shown though to carry the older 75mm M3 gun. Historically the Shermans did eventually get a newer 76mm "M1" gun but they were fitted on a newer turret.
The truck being used to carry the gold could not have possibly carried all the gold. When you take out Odd Ball's and the German's share of the gold: 1/14 of the total = 14,000 bars / 14 = 1000 bars each. That leaves 12,000 bars. With the standard weight of gold bars being ~25 pounds each that would mean there is ~300,000 pounds of gold, or ~150 tons. That is a lot more than the truck they were loading the gold onto could carry. That amount of gold would require nearly four modern tractor trailers to carry.
During the final battle scene where a German tank fires a round at Crapgame, Cowboy and Pvt. Willard, the round knocks debris from an archway as they flee from the tank. Crapgame is knocked unconscious to the ground. The very next scene shows Cowboy and Willard stopping, then turning around to retrieve Crapgame. Pvt. Willard momentarily backs up against what is supposed to be a brick and mortar wall and the wall ripples, obviously constructed of fabric with material painted over it.
When Kelly and the guys ambush the German patrol after leaving the minefield, A grenade is thrown into a group of enemy soldiers firing from across the road. We then see the grenade land, and finally detonate. The problem is that when the grenade explodes, we see the plume of smoke and debris, but we also see that the "can" is dislodged from the ground and visible. When the pyrotechnical experts set a charge for a movie set, it is loaded into a metal or thick cardboard canister and buried just below the surface, and the location carefully marked for the benefit of the actors safety. This separates the explosive compounds from ground moisture and errant spark or flame from filming any action scenes. In this case, the detonation of the charge lifted the can partially out of the ground and into camera range.
When the German Colonel is killed by machine gun fire from the Tiger tank, the flame from the machine gun is clearly pointed to the left (of the screen) as opposed to the target's (the Colonel) actual position which is at the right of the screen.
After the gold is found in one of the cases in the bank, the men start moving the rest of the boxes but in doing so, toss them around and handle them as if they were light in weight. Filled with gold, they would not have been able to handle them the way the did.