With the chamber being a tad larger than the bore, a bore brush can leave stuff there. I realized this with my .22 pistol when I found the coating off the bullets building up in the chamber to the extent that a round would not easily drop into it. Since then, with the brush in the chamber, I rotate the barrel around the brush, at the same time, holding the brush tight against it.That works to keep my .22 chamber clean & I'd think it'd do the same for other calibers.
But, if the buildup is lead, J-B Bore Polish may work better than Hoppes. I've also read recommendations of the 'snakes' as being better than a bore brush, but haven't tried them.