 Here is what Barnes has to say about CR-10 Bore Cleaner on their website: "Barnes' specially formulated CR-10 bore cleaning solvent effectively removes copper and powder fouling. This aggressive bore cleaner quickly loosens and lifts heavy copper deposits left by jacketed bullets as they pass through the bore. Leaves rifling clean for better accuracy, longer barrel life. CR-10 bore cleaner is non-corrosive an won't harm barrels." I tend to agree. I have been using CR-10 in cleaning of barrels in several rifles and handguns since they provided me a sample to test. It has proven to be the most aggressive copper removing liquid I've used to date. It has also proven effective in removing powder residue but is a bit expensive for that chore. I can buy nitro powder solvents much cheaper and use them for the initial cleaning after firing for 3-4 patches and then switch to the CR-10. It aggressively attacks the copper residue in the barrel and removes it better than any product I've yet tried in liquid form. I recommend you not leave it working in your barrel for more than 15 minutes at a time without removing it. The other day I was cleaning two rifles at a time, a Rem 700 LSS Mtn. Rifle and a Ruger #1B and left it in the Ruger barrel for probably 45 minutes or so while changing targets and doing a few other chores. It was left in the R700 LSS barrel for the same length of time. I noticed no ill effects on the Remington but noticed a light coat of rust forming on the blued steel Ruger barrel. It came off quite easily with a single wet patch and I don't feel any harm was done but I can see how leaving one of these aggressive ammonia copper solvents in a barrel too long can cause some etching/rusting of the barrel. Of course following the instructions would have prevented this but I was busy with other chores and let it set longer than recommended. After use I use a single dry patch followed by a couple of patches wet in a nitro powder solvent to follow up the use of this or any other ammonia based copper solvent. I then use another dry patch and if putting the gun away as opposed to shooting it I then follow that up with a patch wet with Barnes CR-10 definitely gets a Graybeard Seal of Approval for cleaning stubborn copper deposits from your rifle or handgun barrels. You can visit the Barnes Bullets Website by Clicking Here Barnes Bullets 1-888-BARNES-X |