Copper fouled barrel in M1D Garand
This is the first time I have had to deal with really heavy copper fouling. I already did a search on removing copper fouling, and did a lot of reading. I'm a chemist, and know about using strong ammonium hydroxide solution that selectively reacts with copper to help remove it. In the M1, I'm aware of plugging the gas port when filling the barrel with liquids.
I just picked up an M1D from a young guy who didn't know what he had or what it was worth. His grandfather passed away some years ago and left him his CMP M1D that has the scope and mount, bayonet, and field cleaning kit that goes inside the butt. The flash hider got lost, though. The receiver has not been re-Parkerized, there aren't any import marks, the operating rod is stamped NM for National Match, it has the CMP carrying case with egg crate foam lining, and there are several enbloc clips. About not knowing what he had, he shot it a lot for years without ever cleaning the barrel. I checked the operating rod and it is not bent from using heavy hunting load type ammunition, thank goodness!
I already put in a lot of time wearing out several bronze brushes, using kerosene to wash out the crud. I've had a few milsurps with copper fouling that I used Bon Ami scouring powder and water to get cleaned out, which worked pretty fast. But nothing like this barrel.
So, is there anything else besides ammonium hydroxide solution, wearing out bronze brushes, and using Bon Ami scouring powder, plus making my arms hurt, on getting this collector's item rifle barrel cleaned out that is messed up with heavy copper fouling?
I've owned an M1 Garand since 1981, which I put a new GI barrel in myself, back when the original barrels were still available.
Thanks!