If the slide lock spring breaks, the gun will continue to fire. The lock up is affected and accuracy is degraded, but at least the gun will continue to function. I didn't say glocks are never sidelined from a malfunction. I've seen plenty of that as well, the worst being barrel lugs sheering off on a G22. In my experience of overseeing hundreds of thousands of rounds through more than 30 semi custom 1911's that are regularly pm'd by an excellent gunsmith, the frequency of parts breakages and malfunctions that shut the gun down completely is much higher than our glocks.