I put a little moly on the gas piston after cleaning and run it backwards inside the gas tube to burnish it in. They i wipe the piston dry and add just a little of fresh moly and assemble it. If we look at some of the well used yugo sks's the gas systems are wornout from not lubing them. I never had a problem with moly in my gas system ever since my very first chinese sks was purchased in the late 80's.
I use moly on all my springs, bolt carrier/bolt and trigger sear besides the gas system.
Its funny how many used semi auto's i have looked at that had dry recoil springs that showed wear.
None of my gas systems that have pistons go without lube(moly).
www.tsmoly.com its the ts-70 moly that i use.
My bolt action rifles, semi auto rifles and pistols and revolvers all get lubed with moly.
Moly;
Eliminates all wear
Reduces Friction
Prevents Galling
Fights Corrosion
Stays were you put it and stays wet even after longterm storage the gun is ready to rock and roll at anytime.
It also speeds up the cycle timing too.
On the trigger sears it can lessen the trigger pull by up to 50% right away and more as it works into the pores of the metal.
Using moly is like having an insurance policy against wear that you'll never use. Not even the bluing on my first sks inside the revceiver has worn off yet to this day. If your seeing any kind of wear at all your present lube isn't working...