So my relatively new s&w m&p15 won’t cycle the action when shooting. The hammer will reset but the bolt wont move at all. This happens with several different ammos, both winchester 223 and winchester/ federal 556.

First thing i did was clean and oil it. No difference.

Then I checked the bolt seals and they are in good shape. When standing the bolt up on it’s extractor side it doesn’t move, but will with light pressure.

I figured something must be wrong with the gas tube so I blew some carb cleaner through the gas port in the action (the nipple that interfaces with the gas key on the bolt). I expected it to be blocked but the cc ran out the barrel unobstructed.

I covered the gas port (in picture) with a piece of masking tape when shooting and gas came out enough to discolor the tape but not blow a hole in it. I know that’s not super scientific but nothing wrong with more info.

I honestly can’t think of anything it might be. Any info helps, thanks