This is an extention of this question: Using dead bodies for material 4: ammunition
The world is suffering from the creatures of fantasy and nightmares which can appear with just a few minutes of warning anywhere, regardless of it being the middle of the street or on top of your bed while you are asleep. It can be a single one, or millions that swarm the area. The world's infrastructure has been degrading, food and supplies are harder and harder to come by. While firearms work well against these creatures the bodies left behind attract and breed both insects and disease. It is not feasible to hold on to area's with low populations as a sudden appearance of many nightmares can wipe them out.
To protect the city several paramilitary and militia groups are trained to seek out and kill any spawned nightmarish creatures. However to increase the chances of civilians who can't wait on those forces while a demon slug is trying to slowly eat their face everyone gets a fire-arm of their own.
The question: what weapon would be suitable for arming all civilians with?
Conditions that apply:
- all civilians are above the age of 16 and have no severe psychiatric problems.
- the weapon needs to be cheap to manufacture. "Cheap" means mostly resource-wise and equipment-wise. High-grade materials are hard to come by with a devastated industrial capacity.
- the weapon needs to be easily maintained by untrained civilians, or require maintenance so far apart that a small group of trained personel can service all weapons.
- the weapon needs to be portable on someone's back.
- the weapon needs to be able to handle a wide variety of makeshift ammo. From glass to calcium to silicon to silicon carbide, anything that can be made out of dirt or dead bodies had to be loaded in the weapon. "Normal" ammunition is going to the trained personel.
- the ammo will be aimed at non-armor piercing.
- the weapon will be used in short-range as civilians are trained to hide and wait while militia's and paramilitaries do the actual fighting. Using their weapons is as a last resort.
- alternative solutions that do not arm the populace is not considered for this question, the fluff demands that the civilians are armed with fire-arms.
I already have an idea what kind of weapon would come out of this. But having an idea is not the same as confirmation.