Hey token...no set screws, but DPMS locktights those bad boys on. You should be able to see a small seam on the receiver side of the tube, probably an inch or two away from the end. The long piece is the threaded freefloat tube and the short piece is the actual barrel nut. You just need to unscrew the tube from the barrel nut which will give you access to it. The holes arranged around the barrel nut are for the gas tube at the top, and the studs on the armorers to remove it from the upper. Usual practice is to heat the tube at that area to loosen the lock tight and then use a quality strap wrench to break it loose. Or the short version...they glue that Damn thing on, so get a bigger hammer and get busy. Obviously the front sight needs to be removed first. Those taper pins can be unreasonable, so if they aren't coming out...hit them harder.