The US have different safety standards for children's toys. As far as I know, the cannons in all US Playmobil sets (apart from the really big ones) are disarmed to prevent kiddies from shooting missiles at each other, but they can be taken apart and adjusted to make them fire again if you have the right parts.
Playmobil's current US cannons
do fire, but not the small ball missiles that the old European cannon had. The US cannon (e.g. from the recent Ghost Ship) fires a torpedo-like missile, with a cross-shaped shaft that clicks into place in the launcher, and varying head designs for a cannonball, orange or blue fire etc.
If Playmobil removed the springs from cannons it would have been a temporary fix until they came up with a US-acceptable design. Playmobil seem to be putting more and more missile launching devices in their knight and pirate themes, presumably because that's what kids want.
I presume the US torpedo design is to stop kids swallowing or stuffing balls up their nostrils. I can't see that a ball hitting the eye is going to do more damage that a torpedo. The torpedos look far less realistic when stacked on a ship's deck, but they are easier to find after launching, so I don't really mind them at all. It is a toy after all.
