Hey, I have a 700 ML and after the first time I took the bolt apart to clean it I started having all kinds of trouble with misfires. It seemed like the firing pin wasnt hitting the nipple. Come to find out I had not reassembled it right...the spring was messed up. Its easy to put it together right once you know how and I've never had a problem since. Check you manual to see if your bolt is assembled right.
Hope that might help.

SC in LR