I'm trying to build a R0991 clone and all I can find are barrels like this (https://www.ballisticadvantage.com/11-inch-9mm-straight-modern-barrel.html) or 16" barrels with FSB pre-installed that I have to get chopped. Any idea of what my options are? I can't find a proper FSB 10.5" barrel for the life of me. As far as I can tell it's looking like I'll have to get a 16" chopped but I was hoping you guys could offer some advice.