I have a mossberg 590 and put around 15 slugs, 30 00 buckshot, and 200 birdshot shells through it in 2 sessions at the range. when i cleaned it today, i noticed nicks inside the aluminun rec. at the top where the bolt must have smacked into it, the magazine tube needed to be tightened into the rec., and the rail inside the rec where the bolt glides along needed to have its screw tightened. Is this normal and what i should expect after this many rounds?