Dennis,
The rifle was likely made by Benjamin Mills or in his shop. He made his own locks and he was known for the "saw handled" stock on both rifles and pistols. There was a display of Mills guns at the CLA show, last year (?). Well, some year!
I found the following on a genealogy website... Do you suppose the info is from Mr. Galien?
This information was forwarded to me by a gentelman putting together a book on Kentucky Gunsmiths. Hope it helps...
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His guns are strongly influenced by the early years he spent in Canada, where the English influence and "saw handled" rifle tang style were used. I'll provide a brief overview of his background. All his stocks are fancy figured walnut, usually with a crotch grain, often called a "feather grain" from the fine feathered figuring created deep in a walnut trunk where a limb (or root) first starts to form. He was noted as a superb mechanic, and as you can probably tell, his locks and triggers are finely made, usually as crisp today as when made.
His working period can be described as follows. Mills was born in New York in 1810, and probably learned the gunsmiths trade from his father, thought to be F. M. Mills of New York and later North Carolina. He became a journeyman around 1831, and soon after moved to Toronto, Canada where he worked for several years, and got married. At least one Canadian rifle is known marked "B. Mills." It's a fullstock, and not yet developed into the later saw handled target rifle style so well known later in Kentucky. Mills then returned to Mason County, Kentucky, where he is listed in tax records in 1839 and 1850 Mercer County census data. In 1841 he moved on to Stanford in Lincoln County, KY. Several rifles are known from Stanford, in the saw handle target rifle style similar to your rifle's stock style. In 1842 he moved to Harrodsburg in Mercer County, KY. By 1842 Mills was so well known for quality rifles that Kit Carson purchased several rifles from his shop in February of 1842, for the subsequent Fremont Expedition to the Rockies. Mills made many fine rifles in the 1840's and developed a reputation well beyond Kentucky. The 1850's were the peak years for gentlemen's target shooting clubs and matches in Kentucky, and Mills made many of the rifles used. His guns were claimed to be of equal quality to the more famous Manton rifles of England or Wesson and James rifles of Massachutes and New York, respectively, In the 1850's Mills' gun shop was large by all standards, employing 8 to 10 journeymen. His guns were shipped all over the United States, as evidenced by surviving shipping cases. In 1858 Benjamin Mills was appointed Master Armourer at Harpers Ferry, He was there when the radical John Brown led an attack on the arsenal and was captured by Lt. Col. Robert E. Lee in October of 1859. In 1860 Mills was back in Harrodsburg in Mercer Co., Kentucky.