I am fixing to get a Mossberg 500 combo in 20 guage for a great price. It comes with the standard 26" barrel and a 18.5" barrel. My question is, what good is the 18.5" barrel? What can I use it for besides home defense? I would like to use it for slugs, as I cant stand the kick from my 12 guage auto, and keep the other barrel for birds. Will it perform?