Where are the side mission rewards in Watch Dogs?

Solution 1:

Some of the things that you unlock are NOT items per se, you unlock the ability to get them. For example you can unlock certain hacking skills, but you still have to spend a skill point in the skill tree to get it.

In this case I imagine that you unlocked the gun in the gun store, so you now can go to a gun store and buy it.

Solution 2:

First check and see if you really did complete the mission, and if so it really should be in your weapon wheel. I played the game out and by the end it can be easy to miss some of your weapons. It should be in the pistol category, but check a few others just to make sure. If it's really not there go to a shop and see if it's available for purchase. If not the game is probably bugged.

Solution 3:

In watch dog 1, you don't have access to every gun all the time.

Go to a gun store and look at what weapons are available to you. Most of the time you have to change your weapon load out after you unlocked them.