I have seen this exact same thing with Rem Oil and other oils if left for a long time and more oil just added over it. I have seen Hoppes gun oil do that in one application if left for a long time. I'm thinking it has something to do with oiling it when wet or dirty and never cleaning it physically. The old paraffin based oils like Pennzoil would do this horribly. I never let WD or any oil puddle or pool. I always wipe or blow out the excess. When I get a gun in like this I use Simple Green to wash this varnish right off.

I have maintained my personal Remington 1100 since day one in 1978 with WD-40 and it has nothing like this in it. I use it for duck hunting and regular trap shooting. It is 100% as the day I bought it other than the rubber gas seal. I changed it about 10 years ago because I felt it wouldn't hurt to put in a new one before a big out of town hunt. The trigger assembly on that gun gets filled with unburned powder, water and residue from firing. It's the dirtiest running firearm I have seen other than neglected Remington semi auto rifles. I use a pump bottle of WD40 to hose down my trigger assembly and then blow it out with compressed air. Then wipe down all the metal with it. Keeps it looking and running like new. I buy it by the gallon and use it for polishing chambers, wet sanding metal, and cleaning things.

For a proper lubrication I prefer Tri Flow to everything else. If nothing else it smells good. In the right conditions I bet even it will varnish up just like in the picture.



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