what brand is the barrel?
When you remove that gas block, look at the gas port and you should see a carbon ring around it. This will tell you if the block was centered over the hole. If it’s not moving at all, I think you have an issue between the gas block or the gas tube. Take a picture of the inside of the upper. Similar to the one above in the link to the water boarding thread. Where does your gas tube land in the upper? It helps to have all the details you can spare.
If I read your post right, it did not move with either BCG you’ve had in there, correct? So we can probably rule it out. Chamber could be an issue, but I’m leaning towards ruling out the gas system first.