Disassemble the bolt and clean it out. You probably have cosmoline impeding the movement of the spring making the firing movement somewhat sluggish.
It's a common mistake to clean all the comsoline off of everything but the interior of the bolt. It must be taken apart and cleaned up. The easy way to do this is to take it apart and throw everything into a pot of boiling water. It'll melt the cosmoline out of every little nook and cranny.