Prove it. You're speculating and regurgitating stuff that seemingly has never been proven. Show me a test where solvents used in gun cleaning have been proven to dissolve or destroy solder or brazing used in laying ribs, lumps, etc. . If solvents did actually do this...you'd see sight ramps on rifles falling off too. The ribs I've seen popped at the muzzle are usually caused by corrosion or the use of cheap and corrosive acid flux (many American made guns used this method due to cost effectiveness), another reason is that on many mass produced guns, the ribs were laid fast and the solder joint wasn't always consistent the whole way down, thin spots and even holes or spaces are not unheard of.
