I converted to the PGW Coil mainspring. It replaced a factory stock mainspring that was only like 2 years old. I had no extra screw tension on the factory mainspring and would get FTF with anything except federal primers. I never tried to add tension, but that might have cured the FTF issue but would have changed the feel of the levering also. The PGW kit has a completely different feel than the stock leaf spring, but with the lightest supplied coil spring my rifle hasn’t had a FTF since and I’ve tried multiple brands of primers all the way up through magnum rifle primers for the AR platform. I’m not going back to stock, especially in the current primer market.