In 1861 and 1862, Eli Whitney Jr. entered into two contracts with his home state of Connecticut for respectively 6,000 and 8,000 rifle-muskets, generally conforming to U.S. M1861 rifle-musket. A number of exceptions to U.S. model, however, were permitted. On the first contract, 40" barrels were in .58-caliber, but were made with 7-groove rifling instead of 3-groove; on the second contract, arms were made with 3-groove rifling. Nosecaps for both contracts were of U.S. M1855/1861 pattern, but were cast in pewter instead of malleable iron. An exception was also permitted in the rear sights, which initially were same 1.25" long base with pierced single leaf that Whitney had used on his Type IV short Enfield derivative rifles, though later the base was changed to conform to the pattern adopted for U.S. M1861 rifle-musket, but still retaining the single leaf. Lockplates were M1861-style marked forward of the hammer "E. WHITNEY / N. HAVEN" on early production and with an eagle surmounting a panoply of flags and trophies over "WHITNEYVILLE" on later production. Barrels bore typical Whitney letter/number code and were adapted to Enfield pattern socket bayonets rather than U.S. M1855 socket bayonets. Later production occasionally bears inspection letters "G.W.Q.".