I sent my Mini-14 back to Ruger this morning. Of the several I’ve owned, none has ever malfunctioned...until this one. It’s a late production rifle, supposedly one of the improved models. About every ten rounds it experiences a failure to fully extract and eject. Sometimes it makes it through twenty rounds, but usually no more than ten. I’m using factory new Ruger 20-round magazines and Speer factory 5.56mm ammunition. The weapon is kept clean. I’m not sure what the trouble is, but suspect inadequate extractor tension. Hopefully Ruger will get the problem corrected.