Although since buying #8226 in 2009, I have restored the rifle to full length, I read just lately about Company H of the 5th Iowa Cavalry having been formed from a company from Nebraska, who were engaged in the cavalry action at Farmington, TN (October 7, 1863) when Wilder's Brigade tangled with Wheeler around Shelbyville and Duck River. The 5th Iowa Cavalry did not receive Spencer carbines until just a few days after 14 November 1864. Before this they had been armed with Hall's carbines, Remington revolvers, and old heavy pattern cavalry Sabres. "Half the men had carbines, the other half revolvers, and each man a poor sabre." But in General Rousseau's raid in July 1864, his command had consisted of Harrison's 8th Indiana Cavalry, 2nd Kentucky and 9th Ohio Cavalry composing the First Brigade, and the 5th Iowa and 4th Tennessee Cavalry and a section of artillery composing the Second Brigade, during the raid revealed the 8th Indiana Cavalry was armed with Spencer carbines.
Of course, prior to October 1863, when the 8th Indiana was reorganized, it had formerly comprised the 39th Indiana Volunteer Infantry (Mounted), being one of the infantry units that Major General Rosecrans had setup, like Wilder's, under the concept of mounted infantry, and equipped with Spencer Rifles subsequent to the first 2000 Spencer Rifles that were sent to Louisville Depot in April 1863.
So either the 8th Indiana Cavalry were armed with both rifles and carbines, or the carbines they carried were rifles that had been cut-down to carbines like was done to #8226? It is certainly an intriguing idea and one that makes a lot of sense given the manner that the Spencer rifle was carried by mounted troops versus a cavalry carbine with swivel on the side. As I described elsewhere with regard to #8226, the trooper who had carried it, evidently used the rear sling swivel to hang the rifle from his carbine sling, given the wear pattern on the buttstock rubbing against a sling swivel on a carbine shoulder sling off the trooper's side. The rifle's barrel would have been too long and unwieldy to have been carried this way had it not been cut-down to carbine length.