Sergeant Chips McGraw
Buffalo Bill (1944) indicates that the fictional Sergeant Chips McGraw was very old for an active duty soldier. The action in Buffalo Bill (1944) covers decades until Buffalo Bill Cody (or BB) retires from his wild west show in the 1910s.
McGraw is portrayed by Edgar Buchanan (March 20, 1903-April 4, 1979) who would have been 40 during filming from 26 July to October 1943. Buchanan is made up to look a lot older with white hair and mustache, but McGraw is still spry enough in 1876 for active Indian campaigning.
When BB gets a letter from the President inviting him to receive his medal, Sergeant Chips McGraw also gets a letter from the President addressed to "Private Chips McGraw, Fifth Cavalry, Department of Missouri".
In real history the 5th Cavalry was created as the 2nd Cavalry in 1855 and renumbered in 1861. In 1876 the military Department of the Missouri commanded by General Pope consisted of New Mexico, Colorado, Kansas, and Indian Territory (Oklahoma).
The letter, dated April 3, 1846 (BB says that is "thirty years ago" making the date about 1876) says that Private Chips McGraw is retired after 20 years service & is signed by Second Lieutenant Philip Sheridan. The PS says it is hoped the temporary delay hasn't caused Private McGraw any inconvenience, signed by Lieutenant General Philip Sheridan, commanding.
It is rare for 60-year-olds to be as spry as Sergeant McGraw in 1876, and would be even rarer for 70-year-olds, so 1806 seems like the earliest probable year for his birth. And when McGraw enlisted in 1826 10-year-old drummer boys or bugle boys were rare, and younger ones even rarer, so 1816 seems like the latest probable year for his birth. Thus McGraw was probably born between 1806 and 1816.
And I wonder if the creators of Buffalo Bill (1944) ever did the math and thought of making a movie about Chips McGraw in the old soldiers' home telling tall tales about his 50 years of heroic service, with flashbacks to younger actors & Buchanan in younger makeup portraying him.
Chronology discussion:
Buffalo Bill (1944) begins as a war with the Cheyenne starts. In real history there was peace with the southern Cheyenne from the Battle of Summit Springs in 1869 until the Red River or Buffalo War in 1874-1875. Unless the war in the movie is as early as the 1860s or as late as 1874-1875 it is a completely fictional Indian war, which is common in western movies.
BB marries Louisa Frederici when peace comes. Her father visits them after "two years" and offers Cody a job in railroad magnate Vandervere's new buffalo hunting business. After an unspecified number of months or years of buffalo hunting, Buffalo Bill is on a buffalo hunt with Russian Grand Duke Alexius, based on a real buffalo hunt in 1872. During the hunt, Louisa tells her husband she is pregnant.
Meanwhile the Cheyenne and Sioux, angered by the buffalo slaughter, begin the Great Sioux War (GSW). As BB and Louisa Cody ride back to civilization Louisa gives birth to a son, Kit Carson Cody, or KCC (1870-20 April 1876 in real life). If this is the same pregnancy as before, then either:
1) Alexius's buffalo hunt, the birth of KCC, and the GSW all happen in 1870,
2) or Alexius's buffalo hunt, the birth of KCC, and the GSW all happen in 1872.
3) or Alexius's Buffalo hunt, the birth of KCC, and the GSW all happen in 1876.
Or this could be a later pregnancy, with the outcome of the previous pregnancy unmentioned.
When BB, Louisa, and the baby return to an unknown fort presumably in Colorado or Kansas, the fictional General Blazier tells BB that the Sioux have fought General Crook (17 June 1876 in real life) & wiped out Custer (25 June 1876) and he needs BB to guide his command to reinforce General Crook. BB leads General Blazier to Warbonnet Gorge to cut off the Cheyenne from reinforcing the Sioux, and delays the Cheyenne attack on the vanguard by dueling Yellow Hand - possible retribution for Yellow Hand's deeds in The Plainsman (1936)? - enabling the main command to arrive and fight the Cheyenne in probably the most spectacular Indian battle in any movie. It is a highly fictionalized version of the Battle at Warbonnet Creek in northwestern Nebraska on 17 July 1876, where BB did kill a Cheyenne brave named Yellow Hand or Yellow Hair.
Upon return to the fort, Sergeant Chips McGraw sorts through "six months" of mail, including a letter from the President telling BB he is going to get a medal for Warbonnet Gorge (actually for Summit Springs in 1869). McGraw calls the president new on the job, so this would be after Hayes was inaugurated on March 4, 1877 - in real history.
BB and Sergeant McGraw travel east, discovering that BB is now famous in the East. The narrator at the beginning of the film says that Buffalo Bill came out of the West and became famous in 1877. This seems to rule out 1870 or 1872 for Alexius's buffalo hunt, the birth of KCC, and the GSW in the movie timeline.