I assumed the BH didn't open because it was closed when I found it after a pass through shot. According to their website it is common for the blades to close. They say the inertia from the bolt slowing down so much on exit will cause the blades to slam shut. Do you guys see this much at all?
It is very common to see this and for precisely the reason stated on their website. Had a block target once that would stop my arrows but the tip of the arrow would poke about 6 inches out the backside of it. Fold from the front style mech heads would always be closed when I went to retrieved the arrow. A piece of paper taped to the target would reveal that they had indeed opened.
99.99999999 percent of the "IT DIDN"T OPEN" stories on the internet are utter horse pucky.