face. When the bolt handle is fully raised the cam on the cocking piece falls in the shallow notch. In this second position, the firing pin tip is still within the bolt face and prevents easy turning of the bolt sleeve when the bolt is drawn back. The rifle cannot be fired unless the bolt is closed enough to allow the cocking piece to fall within the deep notch; in which case, the locking lugs are engaged in the receiver and lock the bolt closed.
No provision is made to block the sear when the bolt is not fully locked. The action is cocked on the bolt’s final closing motion—the sear engages the cocking piece and holds it back when the bolt is closed. The firing pin can be lowered, without snapping the action, by holding the trigger back as the action is closed.
The wing-type safety is fitted lengthwise into a hole at the top of the bolt sleeve. A small spring-loaded plunger in the safety wing engages a shallow groove in the bolt sleeve, holding the safety in place; shallow detents at either end of the groove provide the “off ” and “on” safety positions. Swung to the left, the safety is disengaged, allowing the action to be operated. When the action is closed and the firing pin cocked, swinging the safety to the vertical or to the far right position locks the bolt closed, so it cannot be opened, and holds the cocking piece from contact with the sear. The safety can also be swung to the right, when the firing pin is uncocked, to lock the bolt.
M91 Argentine Mauser rifle, caliber 7.65mm Mauser. This rifle has a 29.1 ” barrel, length 48.6 ” overall, weight about 8.8 lbs.
Top view of the M91 Mauser action.
The sturdy box-like bolt-stop is hinged to the rear left side of the receiver on a stud and pin. A projection on the bolt stop extends through a hole in the receiver and, on opening the bolt, its travel is stopped when the left locking lug contacts this projection. Swinging the bolt stop outward manually allows the bolt to be removed. The thin ejector extends into the receiver through a narrow slot. It is housed in the bolt-stop and pivots on the bolt-stop pin. The bolt-stop is tensioned by a sturdy flat spring, mortised in the bolt-stop housing and bearing against the top surface of the square bolt-stop stud. This spring keeps the bolt-stop closed and against the receiver. The small flat ejector spring, dovetailed inside the bolt-stop housing, contacts the ejector to keep it against the bolt body. A small screw, through the rear end of the bolt-stop spring, holds it and the ejector spring in place.
The bolt-stop is made with a long lip curving upward at its forward end. The end of this lip extends slightly past the left edge of the clip charger guideway. The end of the bolt-stop lip holds the special stripper clip in place. The lip, of course, is also the means by which the bolt-stop can be swung outwards so the bolt can be removed.
The sear is attached to the underside of the receiver and pivots on a small pin. Tension is provided by a coil spring within the sear. The trigger is of the double-pull type and is pivoted to the sear on a pin.
The trigger guard is combined with the magazine plate through which the detachable box magazine enters. Two guard screws, one on each end of the trigger guard, thread into the recoil lug and tang, holding the action securely in the stock.
The single column, five-shot box magazine is extremely well made, with thin sides of spring steel. The top edges of the sides are bent inward slightly to hold the cartridges in place, but can spring outward when cartridges are inserted. The jointed-V follower pivots at the bottom front corner of the magazine box on a screw. This screw also holds the bottom plate of the magazine in place along with a pin (riveted in place and not easily removed) at the rear of the box. Two leaf springs, grooved in place, one each in the bottom plate and lower follower arm, tension the follower to raise cartridges in the magazine. The magazine is guided, and precisely positioned in the action, by a hole in the trigger guard and the guide extension at the bottom of the receiver when the sear is pivoted. A spring-loaded latch, in the front of the trigger guard bow, holds the magazine in place. The magazine, not intended to be quickly detachable, can be removed, however, by depressing the latch with a pointed tool or bullet point, through the trigger guard bow, and pulling down on the magazine. On the M91 Argentine Mausers, the magazine is fastened in front by a coin-slotted, lipped stud. It is riveted into the trigger guard with the lip of the stud engaging a slot at the front of the magazine.
The magazine is normally loaded while it is in the action. With the bolt open, the magazine can be loaded through the top of the action by using a stripper clip or loaded singly by pressing the cartridges directly into the magazine. The magazine could be removed from the action, loaded, and reinserted into the action, but removing the magazine is not easily done without a tool to depress the magazine catch.
Left side of the M91 Argentine Mauser action.
A M91 Argentine Mauser rifle sporterized by the author.
All of the Belgian and German M89, 90 and 91 Mauser rifles and carbines I’ve seen were superbly made and finished. There were no short cuts, crude stampings or soft alloys used in their manufacture. All of the action parts are precisely machined and well finished. I would assume that such vital parts of the action as the receiver, bolt, extractor, firing pin, etc. were made of the best steels available and suitable for these parts, and that they were properly heat treated.
Markings
The serial number, or a part of that number, is stamped on all major parts of these actions. If these numbers match, it can be assumed that all the parts are original. Some parts are proof marked as well. The model designation and the name of the manufacturer is usually stamped on the left side of the receiver. The crest of the government for whom these arms were made was usually stamped on top of the receiver ring, but in many cases this identification was ground off before the arms were sold as surplus.
The 7.65mm Cartridge
All of these arms were chambered for the 7.65mm Mauser cartridge, very popular in years past. It was and is an excellent military and sporting cartridge. With a 150-grain semi-pointed softpoint bullet it has an advertised muzzle velocity of 2920 fps. This places it in a power velocity class between the 308 Win. and 30-06. Therefore, if you have one of these rifles with an excellent bore and want to use it, I’d suggest using its present caliber. The 7.65 cartridge is well designed, and it can be handloaded easily.
Action Strength and Safety
I would judge these actions to be as strong and safe as any other pre-98 Mauser action— the M93 and M95. These actions have no “safety” or “third” locking lug. No provision is made to vent escaping powder gases harmlessly from the action, in the event of a case or primer failure. However, the deeply recessed bolt head and narrow extractor slot actually provide more cartridge head support and coverage than do any of the later Mauser actions—including the Model 98. Nevertheless, though these actions may have been proofed at much higher pressures, when converting to other calibers by rechambering, reboring or rebarreling. I would limit the cartridge choice to those developing less than 45,000 psi. The magazine, bolt head and extractor, as well as the chamber and bore, impose other limitations on the choice of cartridges suitable for this action, which largely limits any conversion to rebarreling only. By rebarreling, the M89, 90 and 91 Mauser actions would be suitable for the following cartridges, none requiring any action changes to be made: 250-3000 Savage, 257 Roberts, 6.5mm Mauser, 7mm Mauser, 300 Savage and 35 Remington.
Gunsmithing Tips
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