Maybe I can provide Carl with some useful information regarding his interest in the arms of the Fifth (New)Cavalry MSM. In the 1863 Annual Report of the Adjutant General of the State of Missouri, I found the following description of this regiment's arms by its commanding officer.
"The arms of the Regiment are rather indifferent and of too many kinds. Eight Companies have originally been armed with Austrian Rifles, which in my estimation is a poor arm for a Cavalryman in pursuit of guerrillas and bushwhackers. We have 633 Austrian Rifles in the Regiment, 633 Revolvers, 320 Sabres, 25 Pistol Carbines, 202 pairs of Holster Pistols, and 50 Cavalry Musketoons. As the Regiment has proven to be one of the best disciplined and effective in the field in this Department, and as the arms with which the Regiment is now equipped are kept in first rate order, the Regiment is justly entitled to be uniformly armed with No. 1 Cavalry arms, and I would therefore draw the attention of the Commanding General to this fact."
Since this memorandum was sent to Colonel John B. Gray, the Adjutant General of Missouri, in December of 1863, this account probably adequately describes the types of arms available to members of this regiment during that calendar year.
I hope this helps a bit.