I have a Glockworx increased power trigger spring installed in my Gen3 g32 and it works very well, i believe it is in the 6lb+ range. I decided to install the same spring in my Gen4 g19 to test out and after assembly the pre-travel in the trigger is almost completely gone. i had the suspicion that for some reason the spring is being stretched more in the gen4 than in the gen3, causing it to completely over-power the stock 5lb striker spring and not allowing the trigger to move back to the full forward position. i don't have a 6lb striker spring to install and test, but i do have a reduced power 4lb striker spring so i thought i'd install that and see if the pre-travel was even worse. after installation of the RP striker spring the pre-travel is completely gone with the trigger bar already fully "stacked" on the connector and ready to break. the only pre-travel in this configuration is about 1/16th in for the trigger bar to engage the striker safety, but there is 0 resistance in the pretravel before the break. is there a difference in the gen4 trigger housing or trigger bar that would be putting more strain on the 6lb trigger spring causing it to pull so much harder than it does on the gen3? imo the result of the 6lb trigger spring and 4lb RP stiker spring in the gen4 is the same as a 1911 SA trigger, but i don't care for it so i removed the trigger spring and went back to stock for now. just thought i'd share my experience and see if anyone has a good explanation for this or similar results with a heavier trigger spring in a gen4 model. thanks in advance.