Ok, I am in the market for a semi-auto shotgun for home defense and fun, and am considering the m-2 tactical and the m-4, both from benelli. What are your opinions of the two action types? Reliability? I have read about 2 and 4 port versions of the m-4-- I thought the gas system was to be self-regulating? What are the pros and cons of the two? Are there any other semi-auto designs I should consider? (I need a semi because the fiancee doesn't feel comfortable with a pump.) Thanks for the help!