Bolt shell props from the Warhammer 40k universe.
Cast resin, painted with acrylics.
Approx. 3" long and 1.25" wide.
A shot with rulers to show the scale:
Bolt weapons and ammo:
Bolt weapons fire self-propelled mass-reactive shells known as bolts, which are timed to explode just after penetration for maximum lethality.
Each bolt is contained within a cartridge which includes a small conventional powder charge. When fired, this charge launches the bolt while simultaneously igniting its solid fuel propellant, which is timed to do so once it is clear of the barrel. The cartridge is then ejected, clearing the breech for the next round, while the bolt accelerates towards the target under its own power.
Information taken from The Lexicanum [link]