Dry Chambers

[PreserveFreedom]

I have seen a lot here talk about swabbing the bore with alcohol prior to loading to remove any lube that could moisten the powder. This makes sense, but I do have a question about this. By stripping the bore this clean, does surface rust form when leaving it loaded for any significant length of time?

 

[necchi]

It's usually the presence of powder fouling or other salts that allows moisture cling and start rust.
An older barrel that has already been subject to even surface rust will be problematic, once it's started it's a constant battle.

This is one of the troubles you'll face with your "matchlock" barrel, crud builds in the right angle drum area of the cva drum breech style barrels, by plugging the end with a vent and making it non-removable you've made it very difficult to clean in that area.
Any oils left in that spot is really a problem, When oil is mixed with heat and powder fouling it turns into a HARD tar like substance that plugs the flash channel. This is why OILS need to be cleaned completely from an ML bore before it's fired.
Many people leave ML's loaded for extended hunting periods with no harm to the bore

 

[Rifleman1776]

You do not need to be overly concerned with this matter. Oils are protective.
Keeping some in the breech area between uses is good insurance.
A common practice is the day before you plan to use a rifle with oil in the barrel/breech is to stand it muzzle down overnight. Next day swab the bore and load normally.
If you are still concerned (some will be unnecessarily, IMHO), just squirt a little carburetor cleaner into the nipple or vent then swab again.