First you want fresh extractor parts:
spring, insert, and o-ring.
Like so:
http://www.bravocompanyusa.com/BCM-E...%20upgrade.htm
You can get them lots of places, but those are the parts you want.
The extractor itself may need replacing too, if its warn, and not getting enough bite.
Start with those parts and see how you do. Clean and polish the chamber too. What brass are you using? Some brass is stickier than others. What does the brass look like? Ripped of rim where extractor was? When my 300 loads get too hot, I get cases stuck in the chamber, but the extractor rips its part of the rim off. Thats pistol port too. Carbine on an 18" should be fine. Not sure about the 0.067... not that familiar with the numbers.