Model 94 .30-30 extractor issues...

[Guest 70below]

I've got a Model 94 .30-30 that has very little use. It was my grandfathers, but I think it was made in the 80's. about 1/2 to 2/3's of the time it will fail to extract. The round will partially extract then the extractor will loose its grip. I've tried slowly opening the action and watching what happens....many times it will be within about 1/2 to 3/4" from extracting then pop loose and vibrate its way back into the chamber (empty brass). I've heard buildup under the extractor claw can do this, but its very clean. Occasionally it will have trouble grabbing the case rim at the indentation at the chamber. Any ideas or suggestions on how to correct this? Thanks!