Bought a used Bushmaster barrel. For some reason (known only to him) the previous owner had removed the front sight tower, but left the gas tube in it. When I got it, I removed the gas tube roll pin, but couldn't get the gas tube off. I don't want to ruin the gas tube getting it out, but I want to remove it for inspection before I put the whole thing together. Anyone have any idea if bushmaster uses some sort of adhesive on the gas tube? Don't want to heat it up if I don't have to.