Improvised firearm or small canon and improvised armour piercing ammunition manual

 Improvised firearm or small canon and improvised armour piercing ammunition manual.

Example (short version):

1 Barrel, strong enough

  Welding something on one side, for closing one end off

  Drilling one hole on one closed end, at the side of the barrel

2 Tungsten carbide (drillbit for example)

3 Sabot (for the ammunition)

4 Propellant powder

5 Fuse

Example 2:

An improvised firearm.

Fully making cartridges. And tungsten carbide bullets.

And something which will strike the primer pocket of the cartridge.

Important: Very dangerous.