Corrected entry: Throughout the first battle at "Hacksaw Ridge" some of the men are seen pulling the pins of grenades with their teeth. In actuality, the pins on the grenades (both modern and old ones) take at least 7 pounds of force to release the pin. If someone did that, they'd either cause severe damage to their teeth or maybe lose a couple.
Corrected entry: When the Sargent is describing the M1 Garand to the men, he calls it a 30 caliber weapon, I believe it is in fact a 30.06 caliber. The carbine was 30 caliber.
Correction: While the M1 Garand uses 30.06, its official designation is "US Rifle, caliber 30, M1."
Correction: Both the M1 Garand and M1 Carbine are .30 caliber. That is, the bullet diameter. Yes, the Garand uses .30-06 ammo, but that is also a .30 caliber bullet. Referring to the M1 Garand as a .30 caliber is correct.
Corrected entry: When Desmond's dad interrupts the trial, he is seen with the Silver Star medal. Desmond's father served in WW1, but the Silver Star wasn't created until 1932.
Correction: The Silver Star Medal was authorized on July 19, 1932 and was a replacement for the World War One decoration, the Citation Star. Recipients of the Citation Star were allowed to exchange their World War One decoration for the new Silver Star Medal. As such, it is not out of context for Desmond's father to be wearing the Silver Star Medal. (Trivia: the Citation Star is incorporated into the design of the Silver Star and is seen at the center of the Silver Star).
Corrected entry: During the whole battle scene there is not one single soldier running out of ammunition, other than by implication (in hand-to-hand combat for example you could assume that they had run short of rounds). We do not see a single shot when ammunition actually is running out, for example by the clinging ejection of an empty M1 rifle magazine or by machine gunners shouting for ammo. No one ever seems to reload. When the sergeant is dragged by Doss, firing his grease gun, he had already fired at the sniper without reloading and then fires a continuous burst of at least 100 bullets. The magazine of a grease gun contains 30 bullets.
Correction: He uses a M-1 Garand to shoot the sniper then switches back to his "belt-fed" greasegun.
Correction: As a dentist, I can assure viewers that normal, healthy teeth can easily withstand the 7 pounds of lateral force needed to maintain a grip on a grenade pin loop while it is pulled. A more likely hazard is that an excited soldier might crack a tooth while biting down on the split ring loop attached to the pin.