The most unrealistic aspect of COMBAT!
I fondly remember COMBAT! from its first-run on ABC in the Sixties. Now that I enjoy the reruns on MeTV, I find the usage and effects of small-arms in the show to be almost as hokey as a Republic movie serial from the Forties. Examples:
1) In COMBAT!,neither an American M1 Garand nor a German Mauser can shoot through an inch of wood and hit the soldier behind it. Reality: there is a WW2 US Army training film titled "INFANTRY WEAPONS AND THEIR EFFECTS" that shows a single .30-06 bullet penetrating a tree trunk AND the helmet of a mannequin dressed in a Wehrmacht uniform. (Narrator: "That Nazi thinks he's safe behind that tree, but he doesn't know what Uncle Sam gave you to throw at him!")
2) RARELY does COMBAT! show an M1 Garand ejecting its sheet metal enbloc clip when shot dry.
3) Saunders repeatedly loses his 1928 Thompson on the battlefield, yet always replaces it with an identical model. In reality, Ordnance would have issued him a newer M1/M1A1 Thompson, or EVEN a M3 grease gun.
4) There are no grenadiers in the squad, carrying M1903A3 Springfields with rifle grenade launchers. The early-issue M1 Garands could not fire rifle grenades, since the tremendous back pressure would cause the gas piston/bolt assembly to recoil so violently as to damage the rifle; by late 1944, a modified retrofit gas valve cut the gas flow to the piston when the M7 grenade launcher was mounted, and the fired blank grenade cartridge was manually ejected after launching the grenade. (The 1954 scifi epic THEM! shows Garands firing grenades at the giant ants.)
5) Hanley's M1 carbine would not have had a bayonet lug in 1944. Most carbines were retrofitted with lugs by Ordnance after the war.