That brush is actually 'hard bronze', and many target shooters won't pass one thru' their bore . . .
Me? Depends on the rifle. I scrub 'Old Betsy' (my trusty '06 Mauser) with a stainless brush about every 18-20 shots. 8^P
OK,hard bronze.Man o man,I bet I never make the mistake again of calling a bras.....Ooops.HeHe.:)