I have a Sig 522 22LR. I bought the piece new from a big box store in 2011. The SN is XA02XXXX. The owner's manual says that the barrel is 16.6 inches and that the flash hider is removable. My gun measures 16.0 inches from the breech to the base of the flash hider and the flash hider is 2.5 inches. As you can see from the pics, the flash hider is most definitely welded. I want to have this barrel threaded for my GM-22 can. Does anyone know what the discrepancy is? Why is the flash hider welded? I think that if I (my gunsmith) cut the barrel at 16.01 inches and thread it, I will be okay. Your thoughts?