Thinking more along the lines of this:
http://www.officer.com/product/10874378/mesa-tactical-sureshell-shotshell-carrier-and-rail-system-for-kel-tec-ksg
Gas tank is a pain to remove because the butt stock is tight, fitting the shell is fiddly, gas tank is good for about 70 pumps, the top rail on mine was a bit loose which is very unlike TM but apart from these niggles it's very fun to shoot. The sound it makes is very satisfying and for CQB out to around 30 meters it's very good. If you don't like gas then get the AA12 with a drum magazine but if you fancy trying gas then the KSG or Breacher are fun to shoot.