I have a Ruger American in .308 Win. and I have had this gun for going on 5 years now. Up until last year, it was an awesome gun and harvested some deer with it no problem. I was sighting it in after putting a new scope on it, and the bolt locked up, not allowing me to eject the spent casing. I have cleaned the gun up and down, and side to side numerous times. I usually shoot 180 grain Remington Core-Lokt round nose, but I have also tried a “less hot” load like federal 150 grain with no success, as it does the same thing. Anybody ever run into this same problem or have any tricks or advice for me?