I partly bought this gun for home invasion protection. So, I have loaded it with 30 grains of Pyrodex {Gun is handy on top shelf of bedroom closet, caps are in a nearby suit jacket pocket } - no wads, just powder & ball- and put Cabelas Black Powder Pistol Lube on all the balls= a small amount on the sides as I loaded [tried not to get a bit that would contact powder] and some brushed on the loaded balls with a tiny artist brush.
I don't want the powder to obsorb moisture and fail, so should I seal the nipple holes with a tine bit of the Cabelas lube too?[/b]
Firstly, let me say that a black powder revolver would not be my first choice for a self-defense firearm. For the same price you could easily buy a modern pump-action shotgun that would be far more reliable and powerful.
One of the biggest problems with BP revolvers is cap fragments can and do easily jam the mechanism and prevent the cylinder from turning, which prevents you from firing the weapon.
That said, if I absolutely had to rely on a BP revolver for home defense, I would absolutely place caps on the nipples.
Under no circumstances would I put grease or anything else over the nipples in an attempt to "seal" the chambers. All this is going to do is increase the likelihood of a missfire if the gunk fouls the powder or blocks the gasses from the cap.
My understanding is that unfired black powder and/or Pyrodex does not absorb moisture. It is the fired residue that has issues. In any case if you live in a modern air-conditioned home you aren't likely to have any problems anyway.
But the last thing you want to be trying to do is cap a revolver in an emergency situation.
If the issue is children in the home, I suggest a lockbox of some type to keep the firearm away from little hands. I understand the hesitation to "lock up your guns" but the truth is most of us are unlikely to be victims of crime but if you have children in the house you are very likely to have curious kids fooling around with things they are not supposed to. Once I had kids I put all the guns in a gun "safe". It's not really a safe, just a StackOn gun cabinet, but it keeps the firearms out of kids' reach.