.54 caliber. 33" round barrel secured by two flat brass spring-retained bands. NSN. Originally browned barrel, color casehardened lock and hammer, brass furniture, walnut stock. Single shot percussion muzzleloading rifle. Lock marked with a {Spread-Winged Eagle}/US forward of the hammer and in three vertical lines HARPERS/FERRY/1852 at the tail. Breech plug tang dated 1850. Mismatched dates on these arsenal altered rifles are not uncommon as they were fully interchangeable guns. Breech with correct small V/P/{Eagle Head} proof and an AW/P inspection mark. Counterpane with the weak W.C.K. inspection of William C. Kirby. Kirby's inspection mark also appears upside down on the right barrel flat, forward of the bolster, indicating that this older iron barrel was re-proofed after the adoption of steel barrels at Harpers Ferry. Patchbox cut-out with the three router pilot holes found on Harpers Ferry made 1841 rifle stocks, but no inspection mark. Spare cone in patchbox. Buttplate without the "US" on the tang, as is correct and with the added rack number 15. Type III long range ladder rear sight is of the 1855 pattern and is graduated 1, 2, 3, 4, 5 on both sidewalls and 5 through 8 on the ladder. 1855 Rifle pattern iron front sight. Rifle equipped with Harpers Ferry added saber bayonet lug on the right side, 3.5" from the muzzle without a guide key. As a result the upper band is the shorter 2.5" variant used by Harpers Ferry on the guns that received saber bayonet lugs on the barrel, replacing the original 3.375" long upper band. Retains original sling swivels and a full-length swelled steel tip ramrod with good threads at the end. These all steel ramrods were added to some Harpers Ferry modified rifles that were intended to utilize conical ammunition. During the production run at Harpers Ferry a total of 25,207 Model 1841 rifles would be produced between 1844 and 1855. Of those, nearly 9,000 would be altered at Harpers Ferry to accept bayonets and would receive new, long-range rear sights. This is one of those later alterations, which took place during fiscal years 1857-1859. According to Moller's research about 4,500 Harpers Ferry Model 1841 Rifles received this alteration, some being newly altered guns that were previously in their original configuration and others being re-alterations of previously modified rifles. He further notes that most of the Type III guns were bored out to .58 caliber, with only about 25% remaining in .54 caliber, like this rifle. A scarce variation on the Type III Harpers Ferry altered 1841 Rifle in .54 caliber. A correct pattern saber bayonet is offered for sale in the accompanying online timed auction.