Pro-Shot Bronze Chamber Brush

Chamber carbon is harder to move than bore fouling because it bakes on under heat and pressure. Bronze bristles cut it loose without going after the steel underneath, which is the reason a chamber brush is bronze in the first place.

Thread it onto a rod, run it into the chamber and turn it a few times, then follow with swabs or patches to carry out what came free. The whole job takes under a minute and it is the step most people leave out when they clean a rifle, which is why sticky extraction shows up on a hot barrel.