The bulk ammo from Cabelas is almost always Ultramax, it is reloaded ammo and not that great in quality, it has been blamed for a few KBs (blown up guns).
On the AR15.com website there is an ammunition section, and in that section is the "Ammunition Review & Reference" which is information gathered from actual users of a product, when you look on the list of makers you will find Ultramax near the bottom of the list, in the details you will see that among actual users of that ammo that
24.2% of the people who have actually used it had enough problems that they won't buy it again,
that's a really bad review!
http://www.ar15.com/content/page.html?id=210