Through most of its service, the 1st Michigan Engineers and Mechanics was equipped with a mélange of long arms. In December 1862, it was equipped with Springfield rifle muskets, Enfield rifle muskets, Model 1842 Springfield muskets, Vincennes rifles, and Muster 1854 Austrian rifles; the typical Civil War ordnance officer's nightmare, By the spring of 1864, the regiment appears to have been completely reequipped with Springfield and Enfield rifle muskets. All of the arms at time of issue were standard weapons, not something modified for engineer service. Can you post a photo of the entire rifle?
Regards,
Don Dixon