John, I'm sure it does aid in keeping grime out of the bolt mechanism but according to Merkel, it assists in the bolt mechanism:

"The differences when compared to a more normal bolt rifle is that the entire bolt is encapsulated within the receiver casing making for a strong design, further enhanced by the locking arrangement of the bolt lugs directly into the rear of the barrel. It is reminiscence of the old Mauser 66 design to some degree."

Rod, I'm a fan of the small straight-tube scopes on full stock rifles. More traditional scopes just seem too big on these, especially since full stocks can be a bit shorter in length.