[RPG] LARP Cannon with actual projectiles

larpphysical-safetyprop-constructionprops

This years story of our fantasy combat LARP features the siege of a city. Eventually this will culminate in a battle, where there is an actual siege of a palisade-type fortification, including siege weapons (we have done this successfully several times in the past).

This year we had the idea to include a dwarven party supporting the agressor: by supplying them with a dwarven siege cannon. What we're still struggling with, is how to make the cannon safe, and fun.

Requirements:

  • It must be safe for our participants – for combatants and the crew manning the cannon.
  • The cannon should shoot real projectiles of some sort
  • The cannon will not shoot at people deliberately, but will instead be used against the walls/gate.*
    • Of course it must still be safe if one of the combatants were to be hit accidentally!
  • A range of, say, 30-50 meters would be nice (could be somewhat ballistic).

Bonus:

  • If at all possible the cannon should make a loud booming noise when fired
  • It would also look cool if there was a nice puff of smoke when fired.

How could we build a cannon which meets our above requirements?

A good answer would include:

  • Experience with cannons (or other "gunpowder" weapons) in LARP
  • What projectile is used
  • How it is propelled
  • How the cannon could be built
  • How special effects could be achieved (sound/smoke/…)

*) The idea is that after X hits with the cannon the gate/some section of wall will "collapse", i.e. be opened manually.

Best Answer

When I used to do pirate LARP we used the guts of a Nerf gun for this. Someone had built or acquired a little gun carriage and dummy cannon and we put the Nerf launcher plus (painted) rocket in it, with a little talcum powder inside the rocket for smoke effects. Pulling a string launched the rocket.

The advantages of this are that the firing mechanism is cheap and it does actually fire a projectile that everyone can see.

The disadvantages are that you need to build yourself a prop to make it look like a cannon and it doesn't go 'boom'.

We tried using the bangers from party poppers inside something that echoes to amplify the sound, but really if you want something to sound like a large 'boom' outdoors then you're going to have to resort to something that makes a large boom, and time your Nerf-firing appropriately.