This is about the coolest thing since sliced bread!
You install this 16" barreled upper onto your Glock, XD, or 1911 frame and you have an instant carbine in many many of your favorite calibers!
You don't need an FFL to buy one or ship one, they are under $450, which there isn't much at all in the AR world for $450 that's as much fun.
You can go to http://mechtechsys.com/ and "build your own CCU" with the options available.
255gr 45 Super runs 1097 from a pistol (938ft/lb) it may run 1325 from this barrel? That is exactly 460 Rowland ballistics right there, 1300ft/lb energy.
255gr 460 Rowland runs 1300 from a pistol, 1550 from this barrel? 1844ft/lb energy. This would be some SERIOUS bear medicine!
I am sure this has been mentioned here before but I have not seen it..