So you guys DO clean with boiling water. Could you elaborate the process? Do you disassemble the rifle completely before doing it? I just can't imagine how it can be done!
It takes me about 5 minutes.
Strip it down, remove the piston, etc.
Lay everything out on your "dirty" towel. Take hot water from your tap, and put it into a measuring cup or a squeeze bottle (I use a squeeze-bottle like one you'd see fast-food condiments in; $2.99 @ a Real Canadian Wholesale for a bigass clear squeeze bottle). Squeeze/pour a healthy dose into the gas tube, filling it and letting it overflow. This will back-wash the gas tube salts into the bore and out the muzzle. Do this over your sink, obviously.
Then, fill with fresh hot water (or if it's hot enough, just keep going) and squeeze the rest of the bottle through the bore. Put your lips around the gas tube and blow out the "drop" that will stick in the gas port because of surface tension.
If the water was hot enough, you'll have a pretty warm barrel/gas tube assembly. Set it aside to dry (on a clean towel), which it should in short order. Wipe the outside if you like; wipe the inside with dry patches if you like.
Run your piston under running tap hot water, and scrub the carbon out of the grooves if it's piling up. Set it aside to dry too (clean towel), which will go much faster if you just wipe it dry first.
Clean and oil the rest of the mechanism while this happens (I find there's not too much blowback through the action into the bolt/carrier, but I give it some love anyway - Breakfree CLP is what I use, but just use whatever you oil the gun with). Takes just a few minutes, and you're waiting for the barrel/gas tube to dry anyway.
Now that your upper assembly is dry, run one oiled patch through the barrel. LEAVE THE GAS TUBE 100% DRY.
Reassemble.
Done.
-M