A conventional .38spl revolver alongside an improvised 2-shot alternative. On this example the rectangular barrel is swung to the side to load and is fired by flicking closed two spring loaded strikers with the thumb. Bog simple but effective.
A quick and dirty improvised firearm assembled using pipe fittings available at any hardware store. Ammunition in this case has been improvised using nail gun charges with the crimp removed and a lead projectile inserted. The weapon functions by pulling back the ball end of the spring loaded striker bar and releasing to fire.