Manually Set Resolution

In Game for Killing Floor, Red Orchestra 2, Killing Floor2 and Rising Storm 2
Drop down the games console with the "`" button on your keyboard and type the following: setrez xy
Where x and y are the resolution you would like it to display.

Editing Killing Floor .inis
Open up your KillingFloor.ini in your killingfloor system folder and look for the following lines:
ResX=
ResY=
And change them to what you would like the resolution to be.

Editing Red Orchestra .inis
Open up your RedOrchestra.ini in your killingfloor system folder and look for the following lines:
ResX=
ResY=
And change them to what you would like the resolution to be.


Editing Red Orchestra 2 .inis
Navigate
to your Documents/ My Games/ RedOrchestra2/ ROGame/ Config location
and open the ROEngine.ini and look for the following lines:
ResX=
ResY=
And change them to what you would like the resolution to be.


Editing Rising Storm 2 .inis
Navigate
to your Documents/ My Games/ RisingStorm2/ ROGame/ Config location
and open the ROEngine.ini and look for the following lines:
ResX=
ResY=
And change them to what you would like the resolution to be.