I have one for one of my shotguns, and one for a .270. I got them both on clearance when one of the local chain stores where liquidating firearms and supplies. I like how they work, seems to get about 90% of the junk out in one good pull with a dab of #9 at the front of it. My only complaint is how hard it is to pull the darned thing through. I worry about it breaking off. I dont use it all the time, but when I need a quick clean it works in a pinch. As far as worrying about it ruining the barrel, if used properly and kept clean it is no different than running a brass or copper brush through your gun. You do more damage with jacketed bullets fired through your gun than with one of these thing. Heck, I bet our ancestors would have loved to have had these available 100 years ago when they where using rope and swabs to clean thier guns with.