Homefront: How to Fix Missing Weapon in the Bus Issue

If you having the missing gun issue in the bus after the truck crash in Homefront, this is solution:

1- Change all settings to the "Very Minimum". Disable all graphical effects in Options.
2- Disable full screen mode and change resolution to 800x600.
3- Restart the game and started a new campaign.
4- This time the gun was there after the cut scene. It was able to pick it up and exit the bus.