I have shot over 2,00 rounds of S&B FMJ with no problems. I have shot all kinds of other ammo with no problems including Jacketed Hollow points. However, I recently shot two boxes of S&B JHP and had failure to feed problems. The cause is still unknown. Also, S&B is now selling some of their range ammo made with brass plated steel cases. This may take a toll on your extractor.