I’m currently using H4831 smokeless powder for the gun cleaner tests. It’s a slow burning powder so it’s pretty safe to ignite. It leaves a baked on powder residue that is pretty hard to remove without a good solvent.

Here is 50 grains of H4831..ready for ignition.

Here is the “baked on” powder residue that is pretty much bonded to the metal surface. It’s very hard to remove without a good solvent.