Well after 50 years of running various things through various bores, I did it. I bought a can of some new foaming bore cleaner copper remover and thought I would try it on my highest round count AR. Worked great. Moved on to an old Winchester model 70 .243cal that seemed to also benefit nicely. It was getting later but I foamed my M1A and let it work a little while. Grabbed a cleaning rod I don't usually use (one of about 8 cleaning rods on my pegboard wall). Stuck a full size .30 cal patch on and gave it a stick in the muzzle end. Hmmm a little resistance right away so I gave it an extra push. Dead stop. No movement. Stuck. Stuck hard. Crap. I tried pushing and pulling. I must have cussed loud enough that my wife called down to ask if I was ok. Bloodied knuckles by this time. I've learned that when I get frustrated enough I'll either get hurt or break something so I quit. Wasn't sure about leaving the product in the bore doing its chemical thing overnight so I hung the rifle muzzle down from the basement ceiling and sprayed the chamber and bore with Kroil and left it. Next day I went back to it. Took it out to the shop and clamped the rod in a vice on the welding table. Pulled on the rifle until the welding table was going to tip. I next made a fixture to clamp in the other vice (bench mounted) so I could slide hammer the rod into it. 3 times, each time successively harder, and it popped out. The bore looks great. My knuckles are healing. Hope it's another 50 years before I do it again.