Just purchased and installed a Lone Wolf Stainless steel guide rod and 17 pound factory rated spring for my G-19.
This past weekend went out to test fire the combination with both 115gr. and 124 gr. ammo and had absolutly no malfunctions.
I like the idea that its a couple of ounces heavier than the plastic stock rod, and can't chip or flex during firing. Rod and spring together were just around $20.
Used Blue loctite to secure the screw onto the end of the rod after installing the spring. Of course, the way the Glock is designed. the end of the recoil spring is captured in the recess of the slide and cannot come out during firing even if the scre backs out and falls off. The screw is there for the sole purpose of capturing the spring when the rod assy is removed from the slide for cleaning.