I don't have any Quik-Clot on the ambulance I work on when I go into work. The best thing for an uncontrolled arterial bleed is first hard direct pressure to the site of the bleed. Then if that's not working apply a tourniquet. You may have heard to only use a tourniquet as a last resort, well all the action in Iraq and Afghanistan has basically re-proven the effectiveness of early tourniquet application. It will stop bleeding in an extremity. Now if it's somewhere in your torso or abdomen that's bleeding heavily in a SHTF situation you're probably in a real world of hurt. You can figure that if you're bleeding from the abdomen or torso anything that is bleeding externally is also bleeding internally at the same rate. Direct pressure again is not going to hurt, but it's going to be a lot harder of a time to pull through an injury like that without rapid access to surgical care.