Realism again?
If you want realism, ok, how do you think people don't die with 50 bullets in thier chest, or 10 bullets in thier head?
Easy!
To get these x100/x50 bullets you're going to mine, swing your sledgehammer few times, getting some rocks from there, then going to workbrench, mixing these rocks and getting metal things and red packets, then you opening old magazine "How to craft toy guns for kindergarten with help metal things and red packets" which you can buy at Hub library, then you making 10mm Pistol with help 1 wooden stick and some random junk and 10mm bullets with help 1 metal thing and some red packets.
And you want this stuff to shoot properly? Of couse you won't kill a person with this kind of weapon and bullets made from 1 metal thing and some red packets.
And now.. how you do a knife? x1 Wood, x1 Junk, it's not even metal! It's wooden stick coiled with random crap found in ruins. Of couse you can stab someone 100 times in the chest and he'll laught after that.