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Posted: 7/3/2025 7:41:01 PM EDT
| Has anyone just used Kriol to clean and removed carbon /copper fouling from their barrels? |
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Kroil is a “creeping oil”, and it’s forte is getting into the tiniest of spaces between parts, which helps you separate seemingly frozen and seized fasteners. I just recently used some for that purpose. But it’s not intended as a cleaner, so what it does in that role is unknown. Test it and see what it does in your barrel. |
| Will not remove copper or hard carbon. It has been recommended when shooting moly-coated bullets, but there are better options. I use Hoppe's #9 for powder residue and KG4 for copper, as well as JB Bore Paste for hard carbon. A Teslong bore scope is so inexpensive that there is no excuse not to own one - it will tell you what your barrels need. |
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yes kroil is half of the mixture when using jb bore bright for both their deep bore scrub and bore polishing compounds as per the retailers of jb bore bright. using kroil alone should work well. it worked for me but i use it more sparingly now due to it burning my eyes when i shoot and get gased out. i was using it on bcgs in ar15s and the gas started burning my eyes really bad. just be sure to wipe it all away when done. as an unrelated side note to anyone reading what i wrote above just be very careful using jb bore bright polishing compounds as it ruins bores quicker than most realize is what ive read online. |
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| My thought is just use Breakthrough Suppressor Cleaner even if you don't have a suppressor. This stuff is amazing and cleans stuff very easily. What I do is simply spray my parts down, then wait about 2-3 hours and come back and brush it off. There's a little bit of picking and a little bit of brushing still left for the very hard baked on carbon but otherwise it is much easier to clean than before. |
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Kroil works well as a stand alone solvent in .22 rimfires and pistols fouled by cast bullets. It gets underneath and loosens Pb deposits so they come out on a brush or patch. The old Kroil/paste technique is still a good approach to heavy laminated metal/powder fouling. After around 18k an 11.5" upper was doing 12 MOA with ball. Borescope appearance was ugly, but distal rifling still looked OK. As an experiment did successive Kroil/USP paste for a couple weeks. Got it back to 4-5 MOA (irons and old fart eyesight). |
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I have a can in the garage, one on my gun bench and another by the metal lathe. It’s good stuff but I think you would be better served with a specific copper solvent. The mildest I have used is Shooter’s Choice, my current go to is WipeOut often using the accelerator first. I have a bottle of BoreTek but I may have only used it once so far. When I store a gun post hunting season or for the winter I leave my bore lightly wet with the basic home made Ed’s red. Even if I cleaned with copper removing solvent I will still get a little more copper out from the slowly working Ed’s Red after it sits all winter in the safe. Ed’s Red is Deoderized kerosene, mineral spirits, Acetone, transmission fluid, (and lanolin if desired). Chemically it isn’t supposed to do anything to the copper but letting it sit all winter I think it creeps under any carbon and copper layers. Then when you patch it you get the old caked carbon powder that was trapped in the corners of the lands. |
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I'm late to this party but I've always felt that Kroil was too expensive to use an everyday cleaner. I have plenty of copper solvents and other specialty bore cleaning products but I use often use "Free All" as a general bore cleaner. Bonus - it's available at most auto parts stores. |
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Kroil is awesome. First and foremost a penetrating oil as previously mentioned. However it has good cleaning properties as well. Will not touch copper to my knowledge but it does great on fouling and will soften hard carbon if soaked. As already mentioned, Kroil is a component in a lot of home brewed bore cleaning solutions. It's also similarly mentioned as a component in cleaning solutions used to remove hard carbon from suppressors. Kroil also excels at removing surface rust with 0000 steel wool. It does not have any protective properties so make sure you follow it with a good metal protectant like Baricade or Rem Oil. Overall, it's worthy of a spot on your bench. |
| Will Kroil damage anodized aluminum parts, like an upper or a rail? I'm planning on running some Kroil down the barrel to remove a stuck bullet and I prefer to not disassemble it if possible. Don't care if it's discolored. |
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Originally Posted By Strela: Will Kroil damage anodized aluminum parts, like an upper or a rail? No. And this is per the mfg. https://www.kroil.com/resources/frequently-asked-questions/ |
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Kroil is expensive and there are better options. CLR will safely strip a barrel and not harm the bore. Ed's Red for general firearm cleaning. Remember, copper equilibrium gives you consistent and best accuracy. Only strip when and if your accuracy starts dropping. |
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Originally Posted By deputy599: Has anyone just used Kriol to clean and removed carbon /copper fouling from their barrels? Also, MPRO-7 works very well. For heavy deposits, I use JB paste. |
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| Kroil is an excellent penetrant but not enough to justify the price over say PB Blaster. |
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| Try KG12. It was developed for military artillery. Very good copper dissolver. Won't dissolve carbon. Won't hurt metal. Put in bore and leave overnight. Clean as normal. Won't leave patches blue like shooters choice showing you dissolved copper. Buy directly from KG. |
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