(Continued from Part 1.)
Mauser Models, and Excessive Head Space
Small Ring (M1893-96) Mausers made in Germany can usually be safely loaded to a maximum pressure of 46,000 CUP. This rule applies to rifles also made in Sweden that used arguably higher grade Swedish steel available at that time. Mauser rifles were at first made only in Germany. Mauser sold essentially the same model with minor modifications, chambered for different cartridges. It is basically the same high-quality rifle that was made to shoot many different cartridges and had minor design differences that the customer requested. It was some like ordering a Chevy model vehicle, that was sold with different accessory packages and nameplates. Some Chevys had a 6-cylinder, and some customers wanted the largest V-8. Correspondingly, the 8x57mm Mauser cartridge versus the economical and low-recoiling 6.5×55 cartridge.
Many Mausers were later made in-country, such as in Sweden, and Spain. Avoid the Spanish Mausers made in Spain, as some of these have inferior metallurgy and tempering. The early-production ones made by teh Ludwig Loewe company of Berlin are much better made. Many examples of La Coruna Spanish arsenal Mausers are found with excess headspace, a serious safety concern. If a cartridge case ruptures, hot gases could escape directly rearward toward the shooter eyes. and face as M93, M95, and M96 Mauser actions do not have a port to allow these gases to escape safely, and away from the face. I personally would only choose Mausers made in Germany and Sweden, as these rifles well-known to be safe.
Reloading Data and Safe Cartridge Pressures for Antique Mausers
When reloading cartridges for these small ring Mausers, particularly the antiques, we should only use load data with pressures measured in Copper Units of Pressure (CUP) used to gauge the rifle action’s strength. This has been used for Mausers made since teh early 1890s. It is a time-tested method. Do not use any load data that does not indicate pressure in other than in CUP. Many newer powders should not be used, because the pressures these powders produce are not measured and recorded in terms of CUP. Many IMR (Improved Military Rifle) powders, and other powders used during the last century were often tested in these cartridges using the original and early techniques. It is a mechanical type of pressure measurement, pressure units in CUP., that has been validated empirically, as safe in these now antique and later-designed cartridges. The modern method that uses PSI (the Pounds per Square Inch pressure unit), is a very different technique, and there is no exact conversion from PSI to CUP, and vice versa. Just stick with tried and true CUP pressure data, and be safe.
Potentially Dangerous Reloading Data for Antique Rifles
Despite the best effort of SAAMI standards, be warned that some reloading manuals such as the Hodgdon 6th Edition, offers a warning — more of a mention than a warning — in the introduction page, but not in the data. I believe that this not acceptable presentation of reloading data. It is dangerous as most ignore the innocuous and mostly useless blurbs that only briefly recount the cartridge’s history. This is not an appropriate place for an important warning about safety. Reloading data is best to have in a printed copy form. On-line manuals are now widely accepted. Regardless, only use publish load data from a company in the powder or bullet business. And only use their data if it offers reloading data accompanied by pressure expressed in either CUP, or PSI, that corresponds to the maximum weight charge that should be listed next to the maximum recommended charge weight. Sometimes these manuals do, and sometimes they do not!
Here is an example of an on-line reloading manual that does not advise that the maximum loads listed exceed the safe working pressures of older rifles by a great deal. It would be very dangerous if used. This example is from a respected company, Nosler. Here Nosler does not provide any pressure measurements for their maximum recommended loads [1]. It would be tempting for the uninformed reloader to use this authoritative source. Hodgdon’s online reloading data [2] does however does list pressures. Hopefully, this oversight has been corrected in Nosler’s more recently published hard copy manuals.
Reloading data, without pressures listed for maximum charges by powder weight, as mentioned, should never be used for an antique rifle. In fact, even if pressures in CUP is provided, be extra cautious when approaching the maximum pressure in small ring Mausers. Although well-made, they are also often well used, and head spacing can become excessive. It is wise to settle for a reasonably accurate load that is below maximum pressure, in any rifle. I do not seek to exceed maximum velocities, and subsequently dangerously high pressures. I am conservative and prefer to preserve my brass, barrel, and my shoulder, not to mention the actions of older rifles. If load data for this and other cartridges for these vintage and antique rifles is found without pressure measurements listed, then assume the data is intended for modern rifles using these cartridges, and do not use this data.
To reiterate, when loading for these old rifles, only use load data that specifically uses pressures listed in CUP. Often we find the two measurements of pressure used side by side, one line might use PSI, and the next line could use CUP. Only use data indicating pressure in units of CUP, and stay below 46,000 CUP. It is also best use the latter method of reloading, and start with a ‘starting load’ recommendations, and work up in no more than half grain increments while carefully inspecting the brass for signs of excessive pressure, and accuracy in your newly-acquired rifle.
If there are no pressure signs at the maximum load weight, and at pressures approaching, yet below 46,000 CUP, then stop there. Use the load that is the most accurate, and that is usually a load that is slightly lower than the maximum, and sometimes is near the beginning, or starting load. If the starting load gives you the best accuracy, you are in luck to have a lower pressure load that is also accurate. Getting 100 f.p.s. less velocity is insignifcant. Accuracy and shot placement, are really where it is at. “Aim small, miss small.” The action and barrel will have a longer service life as a result, as well. There are reports that the Model 1893 actions can handle 50,000 CUP that the original ammunition may, or may not have been loaded to, but I have found that not to be true about all Model 1893 Mausers. Better safe than sorry. It performs adequately well despite the lower and safer pressure of 46,000 CUP. Metallurgy at the turn of the century was more of an art than the science it is today. So inconsistent tempering was more likely.
When Purchasing Ammunition for an Antique, Avoid Trouble.
If you are not a reloader, and purchased the rifle from a reputable dealer, I recommend purchasing ammunition first from Sellier and Bellot, an old European manufacturer of these cartridges. They would know better than most others what makes these rifles accurate, and safe to shoot. However, if the rifle is in rough condition, well used in appearance, or somehow questionable, and purchased from a private party, take it to a competent gunsmith for inspection, and ask them to check the ‘headspace’. If purchased from a reputable dealer, and if it appears to be in very good to excellent condition, use Sellier and Bellot ammunition first to test the rifle. Wear safety glass during this test. If the bolt does not move easily upward when extracting the fired cartridge, do not use this ammunition in that rifle, and take it to a competent gunsmith to have the ‘headspace’ checked. Again, wear safety glasses when first firing, or better yet, always when firing these older rifles that are new to you. Better safe than sorry.
Although a rare occasion, it is possible that hot gases could be blown into the face and eyes, should there be a case head separation, or a ‘blown primer’. You can learn what these terms mean by pick up a reloading manual, and at the same time learn how to check for excessive cartridge pressure by reading the cartridge case after it is spent, even if you have no intention of learning how to be a reloader. Many cartridge manufacturers tend to load these older cartridges on the ‘warm, or ‘hot’ side. You do not want to use this ammunition. Flattened primers are the easiest indication to notice, and a heavy bolt lift is a certain indication that safe pressures for that action has been exceeded. Excessive pressures that go unnoticed can eventually stress, or hammer upon, or ‘beat up’ the softer and older metal in antique rifle actions, that with repeated firings, can cause the headspace to slowly or suddenly increase, and cartridges to rupture. The best way to avoid these safety concerns, and all the worry and risk, is to buy these rifles only from an experienced, well-established, and conscientious dealer who values their reputation. A bargain is not a bargain, especially if you do not know what you are doing. Even a good-looking rifle can have excessive headspace. None of my Mausers that were made in Germany or Sweden have ever had any issues. But two rifles that were made in Spain did have issues.
(To be concluded tomorrow, in Part 3.)