The test was quite a while ago, and I've lost the link, but basically a bunch of solvents were left in short lengths of the same barrel for a certain period, in controlled humidity. As I recall the period was 24 hours, though it could have been longer, and the test might have even been done over two different periods. Wipe-Out without Accelerant showed no pitting, but with Accelerant it did.
I will also note that bore pitting doesn't have to be large enough to be visible to the naked eye to affect fouling.
Will also note, on a slightly different subject, that Dan Lilja is convinced that regular use of JB Compound will increase fouling of bores, by making them too smooth. Dan has some very sophisticated equipment for looking inside barrels, and has performed a bunch of experiments on bore surfaces.
I became convinced he was correct about JB after putting together a .338 Winchester Magnum many years ago. The barrel (not a Lilja) proved to be very accurate, but something of a fouler, and back in those days there wasn't any copper solvent you could leave in the bore without risking pitting. I grew very weary of pushing a solvent-soaked patch through the bore every 15 minutes to get the damn thing clean, so started JB'ing it every time accuracy started to fall off.
But the fouling started building up quicker, even though the bore looked VERY smooth through my Hawkeye. Eventually the rifle would only go 20 rounds maximum before accuracy started falling off, and by then the bore was so copper-coated it just about complete filled the bore, and was very visible even at the muzzle. Cleaning with JB even took longer.
I was about to give up and rebarrel the rifle, when Dyna-Tek Bore Coat appeared. After some experimentation with other rifles, I tried it in the .338 barrel. One application definitely helped, and two reduced fouling to the point where I now only clean it every 75 rounds or so, with a "passive" application or two of Montana X-Treme, because copper build-up is minimal. In fact, those results are what REALLY convinced me of the worth of DBC.
