I'm with Tom on this one. One question, Why? Why add weight to an Ar? Why ruin a perfectly good shot gun? Why would you need both? Why carry two types of ammo? Why would the shot gun do anything (except snake control) any better thant the AR? Why do you think the guys at the range would be drooling rather than giggling (actually given your background they would wait till you left before laughing

). Seriously, there are a hundred things I would buy, including a cat and an autographed picture of Cheney before that rig.
FQ13 who apologizes for being vague about his opion

PS If it were an M-203 on the other hand.....
