you all know about punch daggers right?, a small spike/shanke made of semi-sharp, hardened metal that is short and thin, very hard for someone to disarm you once you're using it, and it's not likely to be caught in a pat-down if it's thin as it should be. some people use something similiar made of quality wood or more likely polymer but with the tip blunt enough to just amplify the striking force of blows without piercing (you can still mess up an organ like the throat/brain/kidneys and how hard is it to use a TINY pocket knife as a push dagger, it's legal anywhere (if someone knows you have it they'll likely push you to give it up or not bring it back but 1 3/4 inches blades are okay in even federal buildings, that's law!
a tiny little knife that 's not much better than a letter opener is still able to stab into someone, and I'm betting a nut-job shooter probably isn't wearing ear plugs so after a few shots, sneak up and neck him (or use your fist, unless a man is old or has muscular dystrophy, what's stopping his fist from connecting with semi-lethal force upon someone's head while totally unaware)
think about it, if someone "blind-sided" you full-force, would you be able to fight back, what if that was done with about 1 1/2 inches of blade sticking out of the fist upon the back of your head or neck. I'm not aware of anyone I've ever met being able to take a hit like that, maybe someone mystical like elmer keith or beowulf, but not some reject with a deathwish