I saw that DPMS makes a  BULL barrel 16inch carbine with a  front sight built for the larger  barrel. Has anyone shot one of these? Is there a great benefit to the super heavy DPMS barrels? I would think that you would want a   heavy bull barrel when your rocking and rolling, the barrel has less whip and does'nt get as hot, or as fast.

DPMS makes bull barrelled uppers in BULL (.936")and SUPER BULL (1.15"?)weights.  These are true bull barrels (read very, very heavy).  While they do tend to heat more slowly than thinner barrels, I wouldn't recommend one if you're looking to "rock and roll".  If you're interested in a heavier contour than standard, check out the HBAR contour.  DPMS bulls tend to please those shooters who shoot targets and/or varmints.  I own a DPMS 16" Bull barrel and use it only for varmints (for which it excels) but wouldn't want to lug it around due it's weight.  I had my barrel fluted, and my rifle still weighs a lot, so I use a bipod most of the time.  For a rapid fire rifle, go with an DPMS HBAR if you've got to have a heavier barrel.  For any other DPMS questions, check out the DPMS industry forum - Jared, the moderator there works for DPMS and can answer any other questions that you may have.