but just in case",
Ever had a revolver with some fairly cruddy chambers? Scrubbing them out can be a pain. For really fouled ones, what I would up trying was a power tool; screwdriver, to be precise*. You can buy a small drill chuck with a hex shank for them(very handy for a number of things). Put it in, lock a bronze brush big enough to be a proper fit into the chuck, apply your favorite bore cleaner, turn it on** and work into the first chamber. You can work it back & forth to make sure it covers the entire surface, then move to the next chamber.
Seems to be a lot less messy than pushing a brush back & forth through, and does a better job of scrubbing. And if you have a worn brush, you can wrap a large patch around it for wiping out, too.
*I've got an orange stick driver that ran $5 at a local tool shop, but you can use a big driver as well.
**Slowly. If it's a variable-speed driver, slowly. you're not trying to drill, just turn the brush in the chamber; with a bronze or brass or nylon brush there's no real chance of damaging anything, but slow speed is still best.