theres that very little hole in the reciever the bent end of the spring sits in. Make sure it's in there, as posted above some don't adjust down very low. I have one FV thats at about 2lbs. the other 2 FV's won't come close, maybe 3 1/2.
I don't care for the accu trigger myself, I actually prefer the old trigger with the set screw for sear engagement. I do like SSS trigger and have them on a few rifles.