The Flare Gun is a cut gadget that was set to appear in Battlefield Vietnam. It still exists in the game files, and much like Battlefield 2's LP7, the weapon has working models, animations, icons, and sounds. When fired, its projectiles will pass directly through any character. When fired at vehicles, the flares will start a small fire which lingers suspended wherever the flare landed.
In an interview with developers from DICE, it was revealed that that projectiles from the Flare gun stuck to players similar to the Tracer Dart Gun and that the reason it was ultimately cut was that it created severe network issues which caused developers to eventually opt to work on the core weapons of the game instead .
Because Battlefield Vietnam features different loadouts for each faction, this list may not be specific enough. Please see each faction's respective page for information on individual weapon kits and loadouts.