But I doubt I have any pics, I get too busy working on stuff to take any

. But to answer your questions, yes, it's threaded into the compression tube, 13 X 1mm IIRC. There's a set screw to lock it, look in the bottom of one of the front stock screw holes. I still have the original barrel kicking around, I'll try to get a pic and get it posted sometime in the next day or so. I've gotten away from this rifle (again!), I've been concentrating on my HPA QB conversion, when I'm not working on restoring out old Airstream travel trailer. Later.
Dave