Howdy

Now that you have mentioned what firearm you are using, may I humbly suggest you use the real thing, Black Powder. I realize real BP is difficult to obtain in some localities, and I completely understand the desire to use more easily obtainable substitutes.

But if corrosiveness is your main concern, real Black Powder is much less corrosive than most shooters believe. The thing that made Black Powder so bad was using it with old fashioned corrosive primers. Then you had plenty of corrosion. I seldom clean my Black Powder guns the same day I shoot them, I try to clean them within a week. Sometimes I have gone much longer. For what it's worth, I just cleaned my 44-40 Henry that I shot a match with last weekend. A couple of patches of my favorite water based BP solvent and the bore was clean as a whistle. No rust, no problem. Furthermore, the beauty of a single shot like a Trapdoor is it is basically just a pipe. No barrel cylinder gap, no complicated mechanism to fill up with fouling. Just a pipe with a plug at one end. Open up the plug and clean it out with a few patches. Done.

Yes, real BP does require special bullet lubes, that is one further selling point for the subs. Pyrodex does require a special bullet lube, just like real BP. But 777 and APP do not require any special lube and can be used with regular bullets with hard cast 'crayon' type bullet lube.

I use Goex or Schuetzen FFg with bullets lubed with SPG in my Sharps.