If I am reading your post correctly and the arrow is pointing to where you think there was a spring - there should not be a spring there. Where your arrow is pointing (and underneath the main spring) there could be a threaded hole for a screw that can be adjusted to set backlash. You do not have to have that screw for the trigger assembly to work, but it will work smoother if you do and adjust it correctly. Your local hardware store probably has an Allen head set screw that will be the right thread size.
Now, if you are talking about a longer spring that comes from the front of your triggers towards the back that in effect puts pressure on the front trigger to provide some resistance and to return it to a forward position - that is a different ball game. Who made the rifle - is it a Commercial made one or a custom made. Knowing that will help in determining which brand of trigger you may have. Once we know that, you can get a quick answer. If it is from a custom rifle, take some more pictures from all the different views of the trigger group and it can then be identified and you will get your answer.