Hi, I want to place a new barrel on my 12 ga auto 5 mag. Is it possible to put a light 12 barrel on it and replace the spring along with a sleeve on the magazine tube? Or a short spring and a a-5 light forearm. Only reason I'm asking is because I have a light 12 invector plus barrel I would like to use. One last question, does anyone know where a replacement barrel for a A-5 12 mag with replacable chokes can be purchased, 26-28". Thanks!