some wondering how to unlock pyro weapon and i got info from IGN...
1. The Flare Gun: The first Pyro unlockable is The Flare Gun, which replaces the shotgun. It allows the Pyro to ignite an enemy at long range, but does require careful aim on their part. It's particularly useful for causing havoc on Snipers and Engineers who want to keep their distance.
2. The Backburner: The second Pyro unlockable is The Backburner. This flamethrower is built for the Pyro who likes to ambush their opponents. It removes the compression blast capability, instead guaranteeing critical hits whenever it's used on an opponent from behind. To aid in survivability, it grants the Pyro an extra fifty health.
3. The Axtinguisher: The third Pyro unlockable is The Axtinguisher. This mighty axe guarantees critical hits on any enemy that's currently on fire, although it's significantly weaker against enemies who aren't. A great combination with the The Flare Gun, or with another Pyro buddy riding alongside doing the igniting.
To unlock these weapons, you're going to have to tackle 10 achievements for the Flare Gun, 15 achievements for the Backburner, and 20 achievements for Axtinguisher. In all there are 35 new Pyro achievements to sink your axe into:
Combined Fire: Use your shotgun to finish off 20 players you've ignited.
Firewall: Ignite 5 Spies who have a sapper on a friendly building.
Cooking the Books: Ignite 5 enemies carrying your intelligence.
Spontaneous Combustion: Ignite 10 cloaked Spies.
Trailblazer: Ignite 10 enemies that have recently used a teleporter.
Camp Fire: Kill 3 enemies in a row, all within the same area.
Lumberjack: Kill 3 people with your axe in one life.
The weird thing i already achieve 13 achievement... y still cant get the flare gun?
13 achievements of the Pyro Pack or overall? If it's Pyro's you should see it in your Character Info and ...something menu.