The following information on the operation of modern Mauser rifles comes from Chapter 15 of Mauser Rifles and Pistols by W. H. B. Smith. Mauser Rifles and Pistols is also available to purchase in print.
A study of the functioning of the first Belgian model covers in general all details of operation of future models with minor exceptions which will be noted in the text. Mauser’s original design was so fundamentally correct that it has never been possible to do more than modify it, and as in our own Springfield (which is a Mauser action), to improve, or more correctly, to refine it to a degree.
As the bolt lever (handle) is lifted to open the action, the cocking stud projecting into the groove in the tang of the receiver prevents the cocking-piece and the bolt plug behind it from turning with the bolt.
The tooth on the cocking stud is thrust back by the cam recess on the bolt thereby drawing the striker back and partly compressing the mainspring. During this raising movement of the bolt lever, the lower end of the lever where it joins the bolt thrusts against an inclined plane cut on the rear face of the cylindrical bridge part of the receiver. This leverage forces the entire bolt assembly to move a short distance to the rear thereby loosening the empty case in the chamber to provide primary extraction (loosening the expanded case in the firing chamber).
After the bolt lever has been lifted its entire travel distance (through an angle of 90 degrees) it ends in a vertical position. The end of the cocking stud now rests in the notch in the rear of the bolt; while the locking lugs have turned out of their locking seats in the receiver and are in the travel grooves in the receiver, permitting the bolt to be drawn to the rear.
As the bolt is pulled back, the ejector springs into its groove. Since the extractor in the face of the bolt is drawing the empty cartridge case back with the bolt, the ejector strikes the opposite lower face of the cartridge case swinging it to the right and thereby freeing it from the grip of the extractor and hurling it out of the action.
The left bolt lug at this point comes in contact with the tooth on the bolt stop, halting the rearward motion of the bolt.
The magazine springs force the next cartridge in line up into the path of the bolt.
Loading and Firing
When the bolt is thrust forward, the ejector is pressed to the left. The bottom of the bolt face strikes the top cartridge in the magazine and pushes it ahead into the firing chamber. As the cartridge is forced ahead, its base is compelled to rise up the bolt face until the extractor catches in the cartridge groove.
When the bolt is about one inch from closing, the cocking stud is engaged by the sear. This results in the cocking-piece and the striker being held back, while the bolt and bolt plug are pushed forward. This action compresses the mainspring completely. (Note: This cocking system applies only to the early Belgian, Spanish and Turkish types. In German and other late types, turning down the bolt handle completes cocking.)
This final motion of course completes thrusting the cartridge forward into the chamber.
As the bolt handle is turned down to the right, the bolt cylinder is revolved and the two lugs at the front end are turned into engagement in the recesses cut for them in the receiver directly behind the head of the cartridge. Pulling the trigger levers the sear away from the cocking stud.
The striker is now released and the tooth on the cocking-piece enters the cam recess on the bolt permitting the striker freedom to reach the primer when released.
If the bolt is not completely closed, the travel of the striker is blocked, since the tooth of the cocking stud is not opposite its entering recess. Hence the rifle cannot be fired.
All Mauser rifles wherever they are made or under whatever name manufactured are merely modifications of this original Belgian design.