wall merges with the ring, which can be seen and felt.
Because the large ring action has a thicker wall of metal surrounding the sides and top of the barrel shank and locking lug recess areas, it naturally is stronger than the small ring action. Just how much stronger is difficult to say. However, German gunmakers considered the small ring action strong enough for the most powerful 8mm military or sporting cartridge. Generally, the large ring actions are preferred and recommended for use with belted magnum and larger rimless cartridges like the 30-06 and 8mm. The small ring actions are preferred for lightweight sporters using small rimless cartridges like the 7mm and 6mms.
Steel and Heat-Treatment
In our study of Mauser actions preceding the M98, we noted that Paul Mauser made each successive action better, stronger and safer than the preceding model through better design. It is generally agreed by experts that the M98 Mauser obtains its strength from its design rather than by the use of specially formulated or alloyed steels, or by some special heat-treatment. It is not known just exactly what kind of steels were used to make the various parts, or the details of the heat-treatments, but there is no doubt that whatever steels and heat-treatments were used, they were entirely adequate to make the M98 the world’s most successful military turnbolt action.
It is believed that the M98 receivers were made of tough quality low-carbon steel. After machining, the only heat-treatment the receiver got was carburizing (case-hardening). This resulted in a hard outside surface to resist wear and rust, but left the core relatively soft for strength.
Receivers of the pre-WWI era, especially the small ring type, tend to be somewhat softer then these manufactured in the 1920s, ’30s and early ’40s. I have observed that receivers made late in the WWII period, or those dated “44” and “45,” are sometimes either very soft or hard, mostly the latter. The normal range of hardness for a good receiver seems to be about 35C Rockwell.
Model 98 bolts and some of the other working parts of the action were evidently made of medium- or high-carbon steel, so that these parts could be made much harder.
There seems to be no evidence to indicate that any re-heat-treatment of a soft M98 receiver will improve it or make it stronger. It is inadvisable, therefore, to have this done.
This brings up a question I’m often asked: “How do I go about selecting a good original Mauser 98 military action on which to build my own custom rifle?”
My suggestions are: Buy the action, or a complete rifle from which the action is to be taken, from a reputable dealer who will refund your money if for any reason you are not satisfied with the action or rifle they sell. Avoid those dated before 1920 and those dated after 1943. Finally, if possible to do so, pick one that was made by one of the better plants. For example, you can hardly go wrong in picking an action made in the 1930s having such names (or code letters) as Mauser, DWM, FN or Brno (VZ-24) stamped on the receiver. After getting one of these actions there is no point in having the receiver tested for hardness; whether it is somewhat harder than 35C Rockwell, or considerably softer, the action is still good.
One final word of caution about very soft receivers: If you have an M98 rifle and you want to use the action for building a rifle—if of pre-1920 manufacture, or if the rifle shows evidence of having been used a great deal—it would be a very good idea to testfire it, preferably with several full-service rounds. After each firing, if the bolt handle can only be raised with difficulty, this may indicate locking lug set-back in the receiver ring. This is usually a sign that the receiver is very soft, and that the locking lugs have hammered depressions into the locking shoulders. The result is that when the bolt is opened the locking lugs must pass from the depressions to the higher undamaged part of the locking shoulders, forcing the bolt forward in so doing. The total set-back may be only a couple of thousandths of an inch, but even so, on opening the bolt the fired cartridge must be forced forward into the chamber the same amount. Such a receiver should not be reused. This condition is not easily corrected and it indicates, possibly, a very soft receiver.
The 8mm military cartridges were supplied in stripper clips. To load the rifle the bolt is opened, the loaded clip inserted into the clip-charger guideway slot in the receiver bridge and the cartridges pushed down into the magazine. The empty clip falls away when the bolt is closed, which feeds the top cartridge in the magazine into the chamber. Single cartridges can also be inserted into the partially empty or empty magazine by opening the bolt, dropping the cartridge in the receiver opening, and pressing it into the magazine with the thumb.
A cracked Model 98 receiver. The crack is located in the left receiver rail where the thumb slot is cut. This usually happens only with late WWII receivers, which were not always properly heat treated, and occurring only if the rifle or receiver is dropped on a hard floor.
The “Short” Mauser Action
The regular or standard M98 action made for the 8mm Mauser cartridge, whether large or small ring type, is 8.75” in length. Various countries using the 7x57mm cartridge as their official military round adopted M98-action rifles that were, in some cases, slightly shorter then the regular 8mm Mauser action. The short Mexican M98 action was once the best known of the short actions. It is 8.50” in overall length. These Mexican actions, either small or large ring type, are scarce. However, during the past few years other short M98 actions have appeared on the surplus market, chiefly the Model 24 Yugoslav.
Here are the dimensional specifications of the short M98 action and the regular length 8mm action:
All other specifications are about the same for both actions.
The short M98 actions have long had, and still have, a great appeal to shooters and gunsmiths wanting to build lightweight sporting rifles for cartridges like the 220 Swift, 257 Roberts, 243 and 308 Winchester. When reading about short actions, the word “short” seems to have a magical appeal and shooters will go to almost any length to get such an action—only to find out later, as shown in the above table, that the short action is not as short or as light as they expected.
Strong and Weak Features
Without question the M98 Mauser is the best, strongest and most foolproof military turnbolt action ever made. It has many outstanding features which have been little improved upon in modern bolt actions, but like all actions, including the latest designs, the M98 Mauser has its faults and weak points. I shall list the various good and poor features as I see them—based on 50 years of experience in using, remodeling, rebarreling and building many rifles on these actions.
As I see it, the only major weak point in the M98 military action is the thumb notch in the left receiver side rail. I have seen a number of these actions with the left receiver rail cracked at this point. I have cracked one myself inletting it into a stock, another when I accidentally dropped it on a cement floor. Once I dropped a barreled action on the cement floor and the entire rear part of the receiver broke off at the thumb notch. Although the entire length of the right rail has no more metal in it than the thinnest part of the left rail at the thumb notch, it seems to be stronger and resists cracking when subjected to strain—much better than the left rail. This is probably due to the heat treatment given the receiver in which a thin area of metal between two larger masses of metal becomes harder, and thus more brittle, than a similar thin area not close to a larger mass. Another example is the receiver bridge; although the entire receiver has been given the same heat treatment or undergone the same hardening treatment, the thin receiver bridge is always much
