Thanks for the info Paul, I found the following on the CR Embassy site in Washington DC:
FIREARMS AND AMMUNITIONS
The admission of firearms and ammunition into the territory of Costa Rica is subject to restrictions and import permits approved by Costa Rican authorities.
Applications to import non-military weapons into the country may be filed by or through a licensed importer, authorized dealer, or a particular person. The Congress of Costa Rica strongly restricts the import of any war weapons into the country; therefore any war weapon in hands of a non-authorized individual is ILEGAL.
Permits to carry personal weapons in Costa Rica are issued by the Ministry of Public Security (Ministerio de Seguridad Pública).
The process to issue these permits will take up to two (2) months, given that all the requested documentation is presented.
The Embassy and the Government of Costa Rica strongly discourage people from traveling with their personal weapons.
However, if you want to bring a handgun, revolver, or pistol you must follow the required procedure:
Inform the airline that you are traveling with a weapon.
Once you arrive in Costa Rica, your weapon will remain at the Customs Office until you register the weapon at the Ministry of Public Security (Ministerio de Seguridad Pública.) at the Department of Firearms and Ammunitions. There, you must provide the following documents:
Official Registration of the firearm with the corresponding authorities of your State of residence (Secretary of State and or Police Department). This document must be duly certified by the Costa Rican Consulate. Please follow the
Police record from the Police precinct where you have legally resided for the last six (6) months. This document must not be older than six (6) months, and must be duly certified by the Costa Rican Consulate. Please follow the
Weapon Entrance Proof of Receipt issued by the Customs/Airport authorities in Costa Rica.
Take a psychological test in Costa Rica to evaluate your personality traits.
Once you obtain the required permits, take them to the Customs Office and your weapon will be released. If you are caught traveling with a weapon without the appropriate permits and registrations in Costa Rica, your weapon will be confiscated and you will be fined, arrested or deported.