Mr. Gale McMillan (may he rest in peace) posted on here some time past regarding these brushes and vehemently recommended against their use. Shortly after I read his post on the matter, I promptly tossed out all tornado and nylon brushes that I owned at the time. All my brushes are now phosphor bronze only.
Apparently, the steel in these brushes is hard enought to wear down rifling prematurely and should only be used if you like replacing barrels frequently. I would be curious to know, however, if they are safe to use for claning lead of out smoothbore shotgun barrels. Anyone?