From your last description, it seems to me the trigger spring is not tensioned. It needs to be above the pin in front of the trigger pin. The trigger spring does not touch the hammer. It loops around the trigger, and when the front of the spring is above the pin forward, it is held forward under spring tension. The first photo shows the spring incorrectly positioned below the pin. Keep in mind the rifle is upside down.











Placing the trigger spring above the pin in front of it, puts it into tension, which holds the trigger forward, which keeps the hammer cocked.










Make sure the front of the trigger spring (the straight part) is tensioned by the pin, and the back end of the trigger spring wraps around the upper part of the trigger. This should cure your 'frustration'.