Cooperation is better for survival then killing people
Also if they live on a farm on the edge of a town then they are more likely to have guns then someone in the center of the town
Try to form friendships with your neighbors and convince them to hoard supplies and guns
If everyone in the community already hoarded supplies and guns then there will not be a shortage where they come to steal
If a neighboring community did not prepare then you will be prepared as a community to fight against them if they attack your community to steal stuff
Nobody can defend themselves as a lone individual against the police & military because police & military are armed gangs