Piime is right why choose. I carry my AR15 carb along with a mossburg 500 with pistol grip and 18 1/2 in. barrel in a sleeve on my vest, both have there uses. Now once Kel-Tec releases its KSG shotgun I might have to switch out the old moss for it...lol
for those who have not seen it... http://www.youtube.com/watch?v=wuVLL5DH_Yc
3-5 month wait if it's your first NFA application, maybe.
My first cleared in about 10 weeks, my second went through in less than a month.