Bryce,

I leafed throught the "MO Adj Gen's Report for the Year 1865" and see that during 1864 Missouri raised the 39th through 50th Missouri Infantry and the 13th and 14th Missouri Cavalry regiments mostly as 6 month units. Not all of these units were completely filled as regiments, but those that didn't at least were able to keep some companies in active duty for the 6 month term. Some of these were filled with former Provisional Enrolled Missouri Militia men and others with former Missouri State Militia men whose units were dismantled or finished their original commitment. I would also suppose that a number of volunteers with little or no previous military experience also joined these units for a variety of reasons.

I have seen that Illinois also raised at least one cavalry regiment of 6 months men (the 13th, if memory serves) that performed duty in Missouri. There may have been others from Illinois.

I'm more into irregular units, so I hope my foray into the world of regulars was factual for you.

Bruce Nichols