Please be more specific. Are you having failures to feed or failures to extract? Are the rounds hanging up on the feed ramp or are they hanging up partially in the chamber? If your gun was running fine before, you may need to replace the recoil spring, or the magazine springs. Do your malfunctions happen with different magazines or only with one magazine? That could mean you have a bad magazine or a weak magazine spring. I have seen well built and fitted 1911s that have gone tens of thousands of rounds without appreciable barrel link wear so I doubt that's the problem. Without knowing more I'd bet that's it's most likely caused by a bad magazine or weak magazine spring or if not that, then a weak recoil spring.