Question for people shooting both semi & bolt guns
 

None of my charge weights/velocity are matching up with reloading data that I've been able to find. I,m usually 150-300 fps slower. I guess because of the pressure bleed off to operate the action.

You are more than likely correct...this is why many reloading manuals have separate sections for 'service rifles' and take into account powder burn rates for reliability and pressure.