Is this a common thing on the R8? No issues with rust anywhere else. Would assume the chamber has the same coating as the rest of the barrel. Thanks
You surely can't be serious ?
The inside of a Blazer barrel is exactly the same as any other steel barrel.No, of course it is not internally coated.
All chambers need separate attention to keep them slick and span. No, fannying about with a .30 mop will achieve nothing, for a .308 chamber you need either a correct size chamber brush, or something like a 45 cal. Bore brush. In phosphor bronze, not nylon. And some fluid designed to attack carbon deposits. Copper is not an issue here, but a decent solvent that's good on both is needed
Your are not keen to allow any preservative oil inside the barrel or chamber ? Seriously ? Well if so it's a dead certainty that it will corrode, unless you are shooting it every day. You don't have to clean it every time, but certainly you need to apply something designed for the job.
Powder residue (call it soot, carbon, whatever) is highly corrosive, when it absorbs humidity from the air the nitro compounds in it turn into a cocktail of nitric and nitrous acids Just remember to clean it out before use, a meths soaked patch, then a dry one is the traditional way.
A proper gun oil (not 3in1 or WD40) will be formulated to be alkaline, or to buffer the acidity.
To reiterate, Blazer barrels are no different inside than any other. There is no protective finish inside. Such a thing does not exist, except maybe rare ones that are chromium plated inside, but that's done for quite different reasons.
But they are so easy to clean properly if you take them off. If this has been going on for a while I'm sorry to say that it won't just be the chamber that has rusted,but the rest of it too. No matter how pristine the outside looks with your external oily rag treatment.
Please learn how to clean it properly, and let's hope it's not too late to recover the situation.