Early on, I would always purchase a breach scraper for each caliber rifle or smoothbore. I found that if I properly cleaned my gun after each time that I shot it, I never needed a breach scraper. I still have all of them just in case I buy a used gun and it hasn't been properly cleaned and needs to have crud cleaned off the breach but other than that, they just lay in my tool chest.
Black powder fouling is easily water soluble and will completely flush out with warm soapy water. That is, providing that you don't make the mistake of using a petroleum based grease or oil on your patches and that you swab your bore well to remove all traces of rust proofing oil before loading your gun. Water soluble lubricants will flush out easily with good warm soapy water along with the black powder fouling. Clean 'em good with warm soapy water after you shoot 'em and you should never need a breach scraper.
Having said all of that, I know it is comforting to have a breach scraper just in case.... :hatsoff: