I did/do the following to keep everything reliable:
1. Polished the contact points of the extractor (approximately half), as well as running the extra power spring
2. Clean the crud out near the extractor after every match/range trip
3. After 250-350 rounds i do feel like all the crud buildup interferes with the trigger action and the feeding action so i always bring an action blaster/degreaser and re-lubricate everything afterwards
I can proudly say ive never had any feeding/extraction problems