Reaching back up the thread a bit...
Mike
I agree completely. As someone who has done a lot of building clearing with an M16A1 and a 18" Remington 870, you're dead on. They're both too long.Just gotta point out: a full-sized M16A4 with 20" barrel is 39.5". A Remington 870 with an 18" barrel (a typical home defense shotgun, I believe) is 37.25". Consider that since most of us do not like the BATFE knocking on our doors, we keep our shotgun barrels a little longer than 18". So really, a full sized M16 is no less maneuverable inside a home than your typical HD shotgun.
Mike