What's involved in field stripping/cleaning the gas system out on that rifle after shooting the corrosive surplus?
The takedown of the rifle is not overly complex, contrary to the reports I had read prior to purchasing mine.
One first removes the cleaning rod. Then one presses the barrel band "release" (a pivoting hasp of sorts which is held in place against release by the presence of the cleaning rod under the barrel), and slides the barrel band off towards the muzzle. I leave mine hang on the bayonet lug. When the barrel band is displaced, one removes the stamped steel ventilation piece from over the gas piston/cup, and then slides the upper handguard forward to clear the rear sight block, and removes it. This leaves the entire gas system exposed.
Then one presses towards the rear on the gas system rod (operating rod?), and removes it from the gas cup. Then one easily slides the gas cup off the piston. With the gas cup removed, one unthreads the piston from the gas block, and then drifts the regulator out towards the rear with a drift/punch.
Cleanup is easy. A patch moistened with Hoppes #9 to wipe down the regulator and the piston, and another with a patch loop to swab out the cup and the gas block. I typically wipe the inside of the ventillated stamped cover and the barrel surface which usually has some powder residue on them. Then, I reinsert the regulator from the breach end of the gas block, and using fingers only, rethread in the gas piston until it stops, indicating that the regulator has been fully seated in its recess in the gas block.
Before tightening the piston, use your 5 sided little gas tool to line up the chosen regulator setting with the line scribed on the gas block, and then snug down the piston. The regulator is held captive and in place by the piston having been snugged down.
Slide the cup over the piston, and reinstall the gas system rod (operating rod?). Replace the upper handguard and the stamped steel ventillated piece, and then slide the barrel band back in place. Secure the entire arrangement by reinstalling the cleaning rod in its recess through the bayonet lug, and under the barrel, and voila! Ready to roll.
The entirety of the procedure sounds much more complex than it is, and while I haven't timed it, I would imagine that in the time it takes to read what I just wrote and digest it, one could accomplish all that is said.
Hope this helps.