i installed a wolff 21 pound rod and spring assy in my G29 yesterday....man is it a lot more stiff than the stock.....hope it works ok with the .40cal long case, im sure it will with the DT. anyway it came with a third spring. what is this for? firinf pin spring or something? is it really needed? i put a 22 pound recoil spring in my G20 and it works fine with everything else being stock. any thoughts? thanks.