Yur supposed to clean the bottom of the cylinders?
I use soap and hot water to flush and patches pushed down then spun on the end of dowel. The wood dowel seems to grip the patches and I can get some leverage on the twist. Works good enough for me.
Edit to add:
I also do the same with my Rifle but with a tight jag. I believe they make a rod mounted scraper but I've only heard of them, never seen or used one.