I’m trying to figure out a problem with a G19 build for a friend. It’s a parts build with Glock small parts but the rest is stuff from Brownells; can’t get any more specific. He built two; one with a threaded barrel and agency comp with a rds cut slide and the other with a standard slide. The one with a comp and dot was failing to eject but firing. The standard one was working correctly. I diagnosed some of the reason the gun with the compensator was having so many issues ejecting as needing a lighter recoil spring. I dropped from 18 pound spring down to a 15 pound spring and was not having as many ejection issues but was having failure to fires, then I dropped a 14 pound spring and was having even more failure to fires. I dropped to a 13 pound spring and could not get any fires at all. Thinking about all of those misfires they all had one thing in common. They were light strikes on the primers and were off-center. It looks like the reason for the off-center and light strikes is that the slide is slightly out of battery when the striker is dropping. One working theory is the stock striker spring is overpowering the lightweight Wolff spring and forcing the slide slightly out of battery. I especially think there’s an out of battery problem as forcing the barrel into battery will fire a primer with a centered strike. (See picture). He says the problem is the recoil spring is too light but I maintain it’s more likely a barrel or slide fitment issue. Any thoughts from our Glock armorers? The pic below shows an off-center light strike and a centered full-strike.