The pictures look like it could be plucked out with a needle nose but the internal burrs must be preventing that..Ball hex wrench was the wrong tool to begin with....probably the wrong size (too small)...some of these screws can be very tight....

Hi-tek has a the best plan remove and replace....

If in a pinch (during hunting season)...I would muscle out the screw with a "vise-grip" or small pipe wrench..or even a hammer & chisel...swallow my pride and file off the burrs...Then drill a small hole thru the BAS from the opposite side and drive the hex end out with a drift punch...fill the drilled hole with silicone and go hunting...