georgy-konstantinovich-zhukov:Model 1817 Harpers Ferry Flintlock Artillery Musket“.69 caliber,
georgy-konstantinovich-zhukov:Model 1817 Harpers Ferry Flintlock Artillery Musket“.69 caliber, 36” barrel length smooth bore. Markings on lockplate in front of hammer of eagle motif over “US.” Markings on the rear of the lockplate in three lines of Harpers over Ferry over 1820.”(Cowan Auctions) -- source link