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NEW M4 piston stuck?


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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.

Edited by thazy2
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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.

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