I have two, a .22 cal. and a .30 cal. (seems everything I own is one or the other

), and use them everytime I leave the range. It really takes care of the powder fouling but won't touch copper fouling. Use the "old fashion" methods for that stuff.
But anything that won't copper foul, ie. has a chrome bore, pistols, rimfires (rifles or pistols), usually gets only a BoreSnake run through it.