I am switching a model 110 from 7mm mag to .308 bolt face. Ordered the bolt face from brownells. I took my bolt apart and the first thing I saw was that the existing 7mag has a large firing pin my new bolt head is a small. Should I open it up or order a different firing pin? The second hiccup is a tab that has been pressed out of the bolt body to engage a groove on the old bolt head. I guess it was to make sure you had everything oriented properly. Can I file this off the inside of the bolt body?