It'll be glued on. The best way I found to remove the flash hider is to heat up some water to very hot or either boiling and stick the flash hider in the water just enough to cover the glue and let it stay in the water for a few minutes then it should be able to twist off. You might have to use some pliers to help with it but remember to take the inner barrel and hop up out of the gun and just stick the outer barrel in the water.