Comming up on finishing my first build. It's been a slow project but I've got almost everything done now. Anyway, while test fitting the gas tube into the FSB I found it to be extreemly tight. Like I can't get in more than 1/4" tight. The FSB is a YHM flip sight and the tube, I'm told, is an Armalite. Only mid-length tube I could find in the entire gun show this weekend. I think the park coating on the FSB is to blame but I wanted to check with you "experts" before I did anything about it. Thanks.

Ok, I got it. I used an allen wrench that fit tight inside the gas block to remove the finish and it fits now...