At the range, I don't use the FA unless it's part of training. On my own, I have never had to use my FA. As far as your bolt not going into battery, are you sizing the case with a full length die? Are you running your rifle wet? Also, since it's a new build, could be just some burr that needs to be smoothed out.
As far as firing out of battery, under normal maintenance and operation, the firing fin can only protrude when the bolt is rotated into battery.
Remove the bolt and carrier from your rifle, press the firing pin forward with your finger, and rotate the bolt with your other hand while watching bolt face for the firing pin. The firing pin will not protrude until the bolt is rotated into battery.