The FARC rebels in Colombia have indicated that they may stop using one of their most devastating heavy weapons (a mortar made out of a propane tank) because its inaccuracy causes civilian casualties. The design for the mortar is known to many rebel groups, and may have first been worked out by the Irish Republican Army. (The proliferation of this mortar design to the FARC and ELN in Colombia and the FMLN in El Salvador, among others, is used half-jokingly by intelligence analysts to support the theory that there must be a "trade newsletter" for terrorist and rebel groups, since they all copy each other's weapons and tactics.) Basically, the top is cut off of a 100-pound propane tank, leaving a thick-walled tube sealed at one end. The tube is loaded with whatever explosives are handy, then with a projectile made from a 20-pound propane tank filled with more explosives. While inaccurate (as it is not rifled) the mortar can throw its projectile half a mile, and the shrapnel from the projectile can cover a radius of 100 feet. The Colombian government has order the manufacturers of such tanks to modify them so they cannot be used as mortars, but there are an estimated 32,000 such tanks in rural areas around the country and, if not already in rebel hands, these are easily accessible to them. Government agents recently found a workshop that turned the tanks into mortars and estimate at least 100 such mortars are in the rebel arsenal. Due to the nature of the weapons, each is used only for a few shots, and some are set to fire on timers and abandoned after use.--Stephen V Cole