You can try running a small pipe cleaner in there to see otherwise you're going to have to flush it with liquid.OK so how do I check the gas system to make sure its properly working?
If it comes out clear, shoot it again. As the other guy said, lube the hell out of it. If you're still having issues you'll need to check the gas block alignment, though if one mag worked I bet that's fine. Check the gas key on the BCG. Make sure it's aligned and clear.
What buffer weight are you running? 20" barrel I am assuming it's a rifle length gas system.
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