NEW M4 piston stuck?

Brand new from FFL today and giving a good going over before the range. One of the piston is stuck. The stuck piston/rod appears to be polished as well compared to the other flat NP3 coated of the other rod. Any ideas?

Is the piston stuck or does the gas plug not want to come off? The plugs are bear to unscrew, usually involving some leverage.

The plug has been removed. The piston is stuck and we know why as well. This M4 was purchased from Impact Gun in Utah as "NEW." Upon closer inspection, the H2O m4 has been tampered w/ or returned with rubberize orange loc tite in several locations. The two pistons are not the same and notched alignment marks are off. See photo below. I think we have been duped by ImpactGuns.

pics[ATTACH=CONFIG]2489[/ATTACH][ATTACH=CONFIG]2490[/ATTACH]

I would take it back.

Let us know how it goes.

This is the newer H2O that lacks the full length tube and cs, right?

The barrel alignment mark is fine. Most m4's look just like that including mine. The issue is the NP3 finish. It adds to the diameter of the pistons. The piston should have been polished by the assembler to fit properly. Tap the piston out with a hammer.

You could make Benelli repair it, but I'd just get some 2000 grit sand paper and put the piston in a drill chuck. Spin it while holding the sand paper. Polish until it fits freely.

The locktite you describe was likely from when the weapon was reassembled after the coating process was completed by Robar.

The piston is stuck inside very tight. I'm certain it will damage the wall camber or bend the rod if the unit is forced out. Both piston rod ends has different beveling. Is this normal? On our our other m4, they appear identical.

pics[ATTACH=CONFIG]2489[/ATTACH][ATTACH=CONFIG]2490[/ATTACH]

That alignment mark is not the end-all, be-all. I just looked at a brand-new barrel still in the Benelli bag, and it is not lined up, either. This NP3 tolerance-stacking is also why I have not jumped on the NiB/NP3/Etc. bus.