First thing I would try is some other ammo. Federal is known for having reasonably soft primers, so try running Federal factory ammo through the gun.
If you still have malfunctions, then it's time to look inside the gun. First, I'd look for any dirt that might be either slowing the firing pin or restricting full movement of same.
Next after that comes issues of weak springs, and for that, you'd have to inquire of Sig what their specs are for their springs.