Colt manufactured approximately 100,000 of these rifles between 1861 and 1865 using surplus machinery from the Robbins & Lawrence Co. that had been originally used to produce Pattern 1853 rifle-muskets for the British during the Crimean War. They were manufactured under contract for the Union Army, for state contracts, and also for sale on the commercial market. The Colt Model 1861s used the same folding leaf rear sight as the Springfield Model 1861. It has the standard markings and features and is dated "1864" on the lock and barrel. The included socket bayonet is stamped "U.S." Though Colt's revolvers are more often associated with the company's contributions to the Union war effort, the Model 1861 rifles would have been more important on the battlefields. Most of the fighting was done by infantrymen with rifles.

Excellent plus, as issued overall, showing mostly bright finish speckled with some brown patina, almost all of the original blue finish on the rear sight, and strong traces of original case colors on the trigger. The crisp wood has some scattered light handling marks and a minor indentation visible along the ramrod channel with crisp cartouches. Mechanically excellent.