I would suggest as a possible scenario.The cavalrymen would have prefered several complete revolvers.Some revolver parts like the barrel and trigger mechanism etc.may have become inoperable and cylinders salvaged loaded and kept for future use.It would seem odd to discard a valuable servicable firearm just for its cylinder.

My first thought was were numbers of extra cylinders manufactured in addition to a complete revolver.Certainly you would think some extra were as replacement parts.Perhaps ordnance purchase reports would give us a clue.

Ive got the Averall book out but forgot to note the page you mentioned before posting this.

Mike