I picked up a Seekins Billet lower today at a gun show....it was described and presented as new.  I cannot get the FCG to work properly.  I picked up a parts kit, not 100 percent sure of manufacture but looks to be typical PSA type stuff.  Installed the FCG and the trigger will not release the hammer...when I rock the hammer back, it will touch the disconnector and they are clearly touching.  The trigger will not release the hammer.  I checked and rechecked the disconnector spring..it is installed correctly..everything is lubed and oiled.

Here is where it gets odd....I removed a FCG from a functioning lower that I have and this FCG does the exact same thing.....I removed it and put it back in it's original receiver and it works fine again.  I am perplexed...and hoping that one of you gurus will point out the ridiculously silly error that I am making and save my day.  :-)

TIA for any help you can give.

So neither FCG will work in the lower?  Out of spec lower most likely.

I hope not but Seekins lowers have a stellar reputation online....it's a very nice piece.

Is the  selector installed? Is the grip installed?  Are the hammer and trigger pins in right-side up?  Did you use the right spring for the disconnector (it's got a larger diameter at one end, but it's often confused with the bolt catch spring)?

I solved it searching the archives....these billet lowers have a trigger adjustment set screw built into them and you need to back it all the way out when installing the FCG...and then once installed adjust it in from there.  Mystery solved.

Yay features you don't realize you have.

Glad you figured it out.  Make sure that set screw is locked down somehow, either with loctite or a jamb screw, don't want it working loose and blocking your trigger.