I am having a problem that I hope someone here can help with. I am working on installing a 9" free float RIS on my 10" AR15 SBR. This of course means I have to remove the front sight tower and install a low profile gas block. I have got everything taken apart, but am having a hard time getting the sight tower to "let go of" the gas tube. Does anyone have a recommendation on how to get the gas tube out of the sight tower.