Weak primer strikes could be caused by a couple things.
First, I'd disassemble the bolt to inspect and clean the firing pin, channel, and spring. There could simply be a lot of factory grease and grime keeping it from functioning properly. If that doesn't fix the problem there could be some fitment issues keeping the bolt from fully seating in the chamber, leaving a slight gap that could produce the light strikes. Try applying forward pressure on the forend as you fire. If this reduces the frequency of light strikes or eliminates the issue, then your new bolt may just need a little fitting...