Bruce,
You are correct that the 1st Mo. Cav. was armed with the Colt rifle early in the war. As with most regiments there was a smörgåsbord of weapons issued. The Colt rifle would have been a cumbersome weapon to handle on horseback & was a danger when shooting with the supporting arm near the front of the cylinder, exposing the hand to flash fire & if the trooper didn't experience that, the heat from the barrel without a forestock would certainly get his attention.
Bass was issued his Remington revolver in 1863.
Ironically, a good friend of mine owns a Sharps carbine that was issued to a trooper (name escapes me at this moment) in Co. H & the reference is from Coate's book on Sharps & is a reliable source.
The 1st Mo. Cav. certainly saw it share of action & had it's hands full dealing with the guerrillas in MO.
I certainly enjoyed the research on Bass & was very fortunate to research him from birth to the time of his death in 1923.