With the completion of his Connecticut contracts, Whitney combined excess parts from its production with some of the unmilled and unshaved lockplates that he still had on hand from his M1855 Rifle Derivatives. The 56 long rifle-muskets that resulted have 40" barrels in .58-caliber, with 3-groove rifling and a rear sight that conforms to U.S. M1861 pattern that Whitney began making in 1863. Flat beveled unmilled lockplates bear two line stamp "E. WHITNEY / N. HAVEN" that Whitney had used on his M1855 rifle-musket derivative and on early M1861 Connecticut contract rifle-muskets, but showing considerable wear, to the extent that the second line is often incomplete or missing entirely. Photograph evidence indicates that the 21st Connecticut Infantry received some of these rifle-muskets. They are often mistaken as a southern purchase, which artificially raises the asking prices.