Gas Piston

Should move freely, correct? Mine was caked up.

You should be able to free it up without taking it out. Heat it a little and spray with brake cleaner or even liquid wrench. Let it soak over night with brake cleaner (don't let the liquid wrench soak that long). It should break loose the crud. Flush it out with wd40 then blow out either with air or fire a few rounds!

I was just recently working to free a stuck piston which came loose with penetrating oil and a magnet pulling and pushing on it. After freeing the piston I found that the nut was barely threaded in, guessing only 1-1/2 turns at the most. I backed out the nut with 2 fingers and cleaned with Gunk Engine De-Greaser... including the gas port hole (small paper clip).
Re-installed the nut lightly oiled, then punch staked it (lightly)
This one came like this from the CMP. No telling what could of happened had I fired it a time or two.

Please Check that the nut is tight. Don't rely on just seeing a stake mark on it.

Shoot Safe,
Charlie-painter777

Nothing catastrophic would have happened. The blown-out piston and nut would be trapped in the slide box under the barrel. When the spring pushed the slide forward, the piston and nut would stop it short of battery so the firing would end right there and you would find out what happened. A really loose handguard might get blown off but that's about it.

I-44,
I was more concerned about wrecking the threads.

Thx,
Charlie-painter777