Just out of curiosity, what was the purpose of the brass ring (photo
20130705_071639) at the end of the Lorenz ramrod for?
When you use a steel ramrod in a rifled barrel you slowly grind down the metal between the rifling.
Since brass is softer than steel it is the ramrod that will be damaged over time and it is much cheaper to replace than the barrel.
So it is to protect the rifling from this wear
The Danish 1863 drill book state that when doing "dry" drill with
rifled firearms, that is with no powder and shot being loaded, then you do not use the ramrods because of this.
Since not drawing the ramrod would sort of undermine the point of drill, all garrisons had a good number of older smoothbore muskets that was used for drill.
edit:
In the 1850ties all soldiers was issued a smoothbore and the 20% best men, when it came to the marksmanskills, was
also issued a riflemusket and got extra training and cartridges so they knew how to use is properly.
So they had two guns and used the smoothbore for drill, and field exercises firing blanks and the rifle musket was only used for live firing on the range. (and combat)
For guard duty they used guns that belongs to the guard, not the unit who happened to do that duty.
(it is the same today in the danish army in Denmark. The Main guard at the base got x guns that you use when you got the guard.)
Then in 1860 the army uprifled a lot of the smoothbores so everyone was issued one.
But old smoothbores was stil used for drill... and guard duty since you dont' really need a rifled gun to hit someone at 20m and guardduty involved the guns being loaded and unloaded daily. So this was a bit hard on the guns.
In a tiny professional army like the prewar US army this might not be an issue. But in armies that was based on training large numbers new draftees each year this was seen as an issue.