Mauser rifle identification, safe to shoot

[Straight_grip]

I have this custom Mauser, it's Spanish made in 24. But is it the safe to shoot version? Or do I have to worry about the bolt coming back and taking out my face. I have shot this gun many times but it has a stigma of the case sticking in the chamber. This was an extremely expensive build thirty years ago and I wanna save it. It's chambered in 7mm Mauser now, would love to remember to .257 roberts.

 

[ants]

Your first post! Welcome to the THR Forum.

If it is indeed a Spanish Mauser, its original cartridge is 7mm Mauser.
That round is safe for the rifle, if the rifle is in good condition.
Commercial ammo keeps pressure at the original design, that's good.

To get rid of any doubt, have a gunsmith inspect for cracks or damage.
He'll charge you for a couple hours of labor, that's fair. And it's worth it.
He will check the two lugs to make sure they are robust and lock properly.
He will check the chamber with a Field Gauge. Might even clean up some rust.

Stick with ordinary commercial 7x57 Mauser ammo and you'll be fine.

 

[Straight_grip]

I'm not gonna lie, competent gunsmith are hard to come by. If you find a good one he's months out. I know it's a 7mm mauser I've put a few boxes thru it. I have only recently been told of the spanish beware scenario.

 

[Robert]

The ones you have to beware of were the ones chambered in 7.62 CETME that were converted to .308. Yours in 7x57 will be fine.

 

[ants]

Robert is right. Now I understand your question: The Spanish Mausers with alleged 'soft' bolts, or was it receivers, or both.
The problem wasn't with the original cartridge, it was converting it to a higher pressure cartridge, that's when the trouble begins.

 

[boom boom]

The issues are several. The Mauser 93 is made of relatively soft carbon steel with surface hardening through heat treatment (case hardening). The 93 is one of the different steps that Peter Mauser took to get to the Mauser 98. The Mauser was designed around the 7mm cartridge with the feeding lips and magazine (which is why the magazine, bolt head, and feeding ramps etc. fit a .308/7.62 Nato). It is somewhat deficient in handling gas from a cartridge separation so the Spaniards bored some of the receiver rings on the left side to allow gas to escape.

The old spanish mausers led a hard life with the Spanish Civil War and colonial wars and was replaced during WWII by a Mauser 98 derivative. These were then used as training rifles, war reserves, or given to the constabulary (the Guardia). These were often not stored in the best of conditions and so many demonstrate pitting (particularly under the stock on the receiver, well beaten stocks and exteriors, sometimes rusted and pitted barrels, and rechambering to 7.62. Sometimes the rechambering has been reported to have used sleeves inserted in the drilled out old bores which is definitely not kosher for these.

The first 93's were made in Germany at Oberndorf but later Mauser agreed to have Spain produce them in Spain. This is what you have is one produced in Spain prior to the Spanish Civil War and cannot tell if you have a carbine, long rifle, or short rifle (which vary by barrel and stock length and what hardware is on the stock.) Some claim Spanish steel per se was softer or that it has more sulfur in it which promotes corrosion, etc. which really has not be empirically verified. What is true is that the Mauser receiver usually has the opposite problem of the notorious 1903 Springfield low number receivers. Mauser receivers including the locking lugs in the receiver have a thin hard surface with a soft steel core. A worn bolt or receiver locking lugs can wear through this level which results in cartridge headspace problems in short order. This is called lug setback and it is really not economically fixable. Sometimes, well meaning sporters read about accurizing Mausers and do things like lapping the lugs--it is very easy to break through the case hardening doing this and basically destroying a useful rifle. Ammo can also do this which is where the controversy over firing Nato 7.62 or .308 Win comes from--lug setback caused by exceeding the design capacity of the receiver lugs. As above, the headspace increases and then cartridge separations occur. These can cause serious injury in the Mauser 93 due to its deficient (compared with the 98) handling of gas from a cartridge separation.

Last, but not least, these rifles are old and may have hidden cracks or other deficiencies based on a hundred years of treatment. If it is original condition with numbers matching, it will probably be worth more as a collectible, even in non-firing condition, than as a sporter.

If you want to sporterize one, try buying a receiver from Sarco--they are 19.95 plus shipping each right now. Then you can have a gunsmith put it together with a modern 7mm barrel (about $100 on up) or a .257 Roberts (a former wildcat based on the 7mm cartridge) for about the same. Bolts can also be had for not much more. I suggest reading Jerry Kuhnhausen's Shop Handbook on Mausers which thoroughly covers the subject with numerous illustrations and pictures. Not a bad idea to have a copy just if you have Mausers as it has exhaustive troubleshooting guides to the various models of Mausers.

 

[tark]

Your rifle is perfectly safe with 7mm ammo. The Oviedo made guns were good quality arms made from good quality steel. Robert summed it up perfectly in post #4. And welcome to the monkey house!!

The best forum I know of.

 

[Ignition Override]

boom boom:
This is what many hours of my reading indicates, in general terms. Do you find that any of it summarizes what you described? I typed this and Then read your very detailed, well-informed post.
Small-ring Mausers (designed for 7x57) have the weaker steel receivers (1890s steel). Many were converted to 7.62 NATO, and some became the FR7 carbine.

In contrast, the Large-ring Mauser receivers in 8x57 should be much stronger than the small-ring. And those L. ring 8x57 receivers in a gun with moderate use should be strong enough to handle both 7.62 NATO and modern comm. .308 ammo with a good safety margin, provided head space is safe.
Many large-ring (8x57) Spanish Mausers were converted to the FR8 carbine, but appears identical to the FR7, other than the original bolts' 'turn down' shape.

Please correct anything here which is not accurate. Even more confusion spread because the Spanish 7.62 NATO ammo was designed to be weaker than standard 7.62 NATO, Not because of the FR8's strength (large-ring), but either for use in the weak Small-ring Mausers' receivers, or for soldiers training with their first CETME "G-3" military rifles (like the HK-91).

 

[Straight_grip]

My rifle posted above is already a 100% custom. 3 step barrel, cheek plate stock. Story goes the piece of wood the stock was made from cost 400$ in the 80's. I don't want the 7mm due to extraction issues I'm leaning towards it having headspace issues or the chamber is not teamed correctly to much or to little. The only thing spanish here is the action. It has had plenty of mill work to clean it upand I wanna save it and turn it into something I want. So question is what model is this one? And can it handle the .257 Roberts pressure which is about 57000 PSI
Compared to the 7×57 or 7mm 50000 PSI ?

 

[Slamfire]

I have written about Mauser receivers, particularly M98 receivers, and their strength levels. This issue pops up all the time, such as in this thread where posters use current day pressure standards, make unsubstantiated claims for period proof test levels, and thus declare that a military FN Mauser is perfectly adequate for chambering in 338 Win Mag:
http://thefiringline.com/forums/showthread.php?t=545699&highlight=mauser&page=2

I disagree with assuming period pressures based on today’s standards. I have not found an explicit statement to the design loads that Paul Mauser used. SAAMI and CIP standards were established well after his death. However there is information about the proof pressures used in M98 actions.

Rifle Magazine Issue 159 May 1995 Dear Editor pg 10

http://www.riflemagazine.com/magazine/PDF/ri159partial.pdf

Ludwig Olsen :
Mauser 98 actions produced by Mauser and DWM were proofed with two loads that produced approximately 1000 atmosphere greater pressure than normal factory rounds. That procedure was in accordance with the 1891 German proof law. Proof pressure for the Mauser 98 in 7 X57 was 4,050 atmospheres (57, 591 psi). Pressure of the normal 7 X 57 factory load with 11.2 gram bullet was given in Mauser’s 1908 patent boot as 3,050 atmosphere, or 43, 371 pounds.

While many Mausers in the 1908 Brazilian category will likely endure pressures considerably in excess of the 4,050 atmospheres proof loads, there might be some setback of the receiver locking shoulder with such high pressures

Kunhausen shows similar numbers in his book : “The Mauser Bolt Actions, A Shop Manual”

Rifle & Carbine 98: M98 Firearms of the German Army from 1898 to 1918 Dieter

M98 Mauser service rifles underwent a 2 round proof at 4,000 atm gas pressure, 1 atm = 14.6 psi, 4000 atm = 58, 784 psia. Page 103. A comment on the metallurgy and process technology of the era, Dieter found records that indicated that the bolt lugs broke on 1:1000 of GEW98 service rifles used by the Bavarian Army Corp!

Gun Digest 1975 has an excellent article, “A History of Proof Marks, Gun Proof in German” by Lee Kennett.

“The problem of smokeless proof was posed in a dramatic way by the Model 1888 and it commercial derivates. In this particular case a solution was sought in the decree of 23 July 1893. This provided that such rifles be proved with a government smokeless powder known as the “4,000 atmosphere powder”, proof pressure was 4,000 metric atmospheres or 58,000 psia. The 4000 atmosphere proof was standardized for the 1893 and continued after 1911.

From the data I have seen the 7 X 57 was proofed at the same pressures as the 8 X 57, and cartridge operating pressures were the same. The 1939 German proof law called for proof at 130% of service load pressure. From Mauser Bolt Rifles by Ludwig Olsen, page 134, The maximum working pressure of the German 7.9 sS cartridge was 46, 926 psi. According to sources, this round was used in machine guns after WW1 and then shortly before WW2, became a universal issue round. Use in the K98 action had to have been examined, and I expect the decision to use in the K98 would have been based on the improvement of metal quality and process technology. A proof pressure 7.9sS would be 61k psi.

Unless someone can produce credible data as to the proof standards of later Mauser actions, and the design limits used by Paul Mauser, I am going to state that it is reasonable that the M96 and M98 action was designed to support cartridges of 43, 371 psia with a case head diameter of 0.470”. Later higher pressure ammunition was probably considered an acceptable risk, but even then, the 7.9 sS cartridge pressure was 46,926 psi.

I believe that a pressure standard for these WW1 era rifles of 43, 371 lbs/ in ² is reasonable. Therefore loading these actions to 50,000 psi, or 60,000 is inappropriate as the locking mechanism is being overloaded. What could happen with these old carbon steel receivers is receiver seat setback, lug set back, all leading to excessive cartridge case protrusion. At some point, when enough unsupported case is hanging out of the chamber, the cartridge sidewalls will rupture. This is particularly dangerous for the M96 actions as this rifle has fewer gas venting safety features, though that point is probably moot if the receiver ring blows off.

“German technology” and “old world technology” are sales terms used all the time by Gunwriters shilling for old surplus guns. Based to these quite undefined terms, many in the shooting community have a very high opinion of old German made firearms. What is true is that the Germans tend to be forward leaning in producing well designed and well made products, but, space ships were not parked in the Zeppelin hangers. In as much as the Germans were using the latest technology in their factories, period German steel was still being made using pre vacuum tube technology and process controls and this is revealed by period material assays.

The following was written by Mauser M98 fan boys, but the numbers are what is important. .
http://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/4281076061?r=8481020161

Okay, here we go again. Sorry, I'm paraphrasing Duane Wiebe.

The 1996 "core" assay of a generic WW-I era 1898 Mauser receiver:

Carbon: 0.29%
Sulfur: 0.022%
Phosphorus: 0.019%
Manganese: 0.45%
Silicon: 0.16%
Nickel: 0.05%
Chromium 0.02%
Molybdenum: <0.01% (trace)
Vanadium <0.01% (trace)
Copper 0.17%
Columbium: <0.01% (trace)

The 1996 "core" assay of a WW-I era 1898 Mauser bolt:

Carbon: 0.18%
Sulfur: 0.018%
Phosphorus: 0.014%
Manganese: 0.76%
Silicon: 0.23%
Nickel: 0.29%
Chromium: 0.06%
Molybdenum: <0.01% (trace)
Copper 0.15%
Aluminum: 0.02%

According to Dieter Storz and his book Rifle and Carbine 98 the material specifications for German barrels and receivers, up to 1918 were:

Carbon LT EQ 0.40”
Si LT EQ 0.30%
Mn LT EQ 0.90
P LT EQ 0.04%
S LT EQ 0.06%
Cu LT EQ 0.18%

Physical Properties

Stability 78, 242 psi
Elastic limit 36,987
Stretching 15%


Everything that was not iron, carbon, manganese, and copper in the fan boy's post is a containment. The assayed parts show a lot of containments. These are elements that the Bessemer type process was unable to oxidize and were left in the material. They reduce the material strength and fatigue life. I don’t know why the Germans wanted copper in the mix, if they wanted copper, but it could have been to make machining easier. Copper, like the phosphorus, sulfur, detract from steel physical properties. And the point of this, this is the vaunted “German Technology” of the period. I will assume American steels had even more containments, which makes period American bolts and receivers even weaker.

As an example of period material strength:

Rolling Block strenght

http://castboolits.gunloads.com/showthread.php?52526-Rolling-Block-strenght/page2

I did not know this until I looked as a response to your post. However, I have worked with Steel my entire professional career. I was the head of a Testing Lab in a steel manufacturing facility for 4+ years. During that time, I was provided a ferrule from a WW1 fighter airplane for testing. It was made from what was labeled "high strength steel" (the label was from WW1). I tested it and found that it was lower strength than the lowest strength steel that can be bought today. In addition, it had a lot more impurities than would be allowed today, particularly sulfer. (PS. "today" means from about 1975 to 1980). I know that steel has continued to increase since then in strength, ductility, and all the other desireable characteristics we use without thinking about it.

I can’t prove that it is unsafe or safe to use any particular WW1 era receiver. I can make an argument about the technology of the period. But as a class, understanding the period technology, shooting the things has some risk. Knowledge would reduce the risk, but I doubt you are going to conduct an extensive metallurgical analysis. But if you are, I offer this as a start: determine the chemical constituents in the steel, determine the hardness of the piece, the grain structure (martensite, pearlite, all the lights) and a test of the yield and ultimate strength of the steel in the receiver.

People today project our current technological state backwards. I can say, from personnel memory, there was a time before cell phones, internet, integrated circuits, and even, air conditioning in cars! (I should remember being miserable without automotive A/C, but I don’t, and I don’t know why) Technology moved very quickly in the early 20th century. Electrical production is negligible before 1902. Prior to 1920, most homes and factories did not have electricity. According to the US Census Historical Statistics of the United States, Colonial Times to 1970, in 1914 30 percent of factory machinery was run by electric motors, but 70 percent by 1929. It has been estimated that in 1912, 16 percent of the population lived in dwellings with electricity, but by 1929, the number was 63 percent. In 1906 total production of electricity for the country was 6,809 kilowatts, by 1920 it was 19,439 kilowatts, and in 1970, 360,327 kilowatts. For me 1970 was not that long ago, and yet, we did not have the internet, cell phones, cable television, things that we take for granted today. I really cannot conceive living in the world before residential electricity or residential sewage and utility water. Spain was even worse than the US in the early 20 th Century. Spain was poorer, the infrastructure worse, which does not fill me with a high degree of confidence on their rifles.

Shoot light loads in the thing and you should have no problems what so ever. Push the loads, and you are in unknown territory.

 

[H&Hhunter]

Plain and simple. A small ring Mauser is not as strong as a large ring Mauser. Don't use high pressure loads or convert a small ring Mauser.

 

[boom boom]

Slamfire is giving you the technical reasons why anyone with old rifles should be circumspect in their use.

This is my perspective from assembling and having old pre WWII Mausers including the 93/94/95 series.

If you are already having headspace issues with a 7mm, it is probably not the barrel nor chamber but lug setback in the receiver--it is possible that before you bought it that someone loaded hot 7mm ammo and fired it through that gun or it could be wear and tear. Another possibility, is that someone tried to lap the bolt lugs and receiver lug recesses for a better fit and simply abraded the case hardening away. Old rifles often tell no tales of what has been done to it. First, I would advise a trip to a competent gunsmith to have it checked. If not that, then I would strongly advise you to buy and read Jerry Kuhnhausen's Mauser Shop Manual which is about thirty dollars via Amazon, Ebay, or Midway (don't buy the ultra high priced ones claiming rarity as the book is still in print despite Kuhnhausen's demise) which may or may not be cheaper than a gunsmith visit.

Here is a link to an image via Google search showing a receiver with lug recess setback--while it is a 98 receiver, the principle is the same
http://preview.tinyurl.com/yaahdhcx

If you have an angled mirror and a small headed led light, you can usually see gross abnormalities if the face of the receiver's lug face looks worn, ridged, bulged, etc. Depending on the size of your fingers, sometimes you can feel it as well if you have a good sense of what you are looking for. Cheap borescopes that attach to a computer or smartphone can also help as well because your extraction problems could be caused by a deformed chamber, unseen gunk, etc. And yeah, I know higher quality borescopes can tell you more, but the cheap ones are good for detecting large problems.

Rebarrelling to the .257 Roberts (which you appear to be quoting the +P pressure which is not recommended for these old 93 Mausers anyway) even if the barrel is initially set to perfect headspace is unlikely to be successful as lug setback will continue to get worse as the receiver is too worn to use. (Think of the lug recesses like a hammer--most hammers are case hardened but when they hit something too hard or with too great a force (aside from chipping), the soft core gives way and the hammer head deforms under the pressure.) Deformation can occur if the case hardening is worn through, through some ill though alterations in the past, or if the firearm was subjected to too much pressure. A few people try to use different bolt (as Mauser bolts can vary in length a bit) to make up headspace but if the receiver is shot, then the longer bolt lugs won't hold headspace long.

You may not want to hear this, but if your receiver is knackered, then
What you can do is buy a new used stripped receiver (Sarco has them for 19.95 plus S/H in what condition I do not know) or from Gunbroker for not much more (can see the pix) and do your barrel swap to .257 Roberts or keep the 7mm barrel if it is ok (use a gunsmith unless you know how to set headspace on a Mauser, time sights, D&T the receiver, or know a machinist friend who also knows firearms) and swap the rest of the parts.

I wish you good luck.

 

[Slamfire]

I have shot this gun many times but it has a stigma of the case sticking in the chamber.

Missed that. So eager to cast dispersion at old guns, totally ignored an important point. Luckily, boom, boom caught it.

In my opinion, the most likely cause is significant receiver seat set back. As the bolt pounds down the surface of the receiver seats, you now have to resize the case to get the bolt open. This happened to me years ago with one of those dangerous National Ordnance M1903A3 receivers. These were cheap cast receivers and the metal was soft. I think they were made in Spain in the 1960's. Luckily, I stopped firing the thing, and it was not till years later that I figured out how dangerous the things are.

I have not re hosted my Photobucket pictures on a blown National Ordnance M1903A3, but the shooter's face was bleeding, all over the place, there was blood on his shirt. Another shooter posted that he still had brass particles in his eyes when his National Ordnance blew up, and that his eyes hurt, from the brass heating up, in bright sunlight.

This however is an example of what happens when a receiver is annealed. This drill rifle receiver, made of good modern materials, was heated up with a torch and it lost its heat treatment. So the metal was soft, it set back as the owner shot it, and finally, with excessive cartridge case protrusion, the case sidewalls gave way.

 

[boom boom]

Thanks for posting that Slamfire. Those bogus 1903/a3 National Ordinance receivers and rifles keep popping up on Gunbroker and often they are titled 1903 or 1903a3 rifles which they are not. Buyer beware. Wasted my clicks on one such listing today.

 

[Straight_grip]

So can someone tell me what model my mauser pictured above is?

 

[Slamfire]

Need more pictures, but you can examine the images on this web page and decide for yourself.

Identifying Spanish Mausers Models 1893 and 1916

http://masterton.us/Spanmauhome

I rehosted my National Ordnance atrocity pictures and condensed them into two jpg's. Anyway, this is what you have to look forward to if the receiver seats set back and the case head blows.

 

[boom boom]

So can someone tell me what model my mauser pictured above is?

Without more pictures, barrel length, etc., it is difficult to tell and some of the indicators are the stock, barrel, sights, etc. along with serial numbers which you may not feel comfortable sharing online. It being sporterized also might have a aftermarket barrel with no sights. My suspicion is that you have a 1916 model used by the Army (the Guardia had a separate crest for its rifles). Many of the converted rifles used the older vizier (roller coaster) type sights called Type I Model 1916 (have no idea what the Spanish called them) while others used the more modern tangent sights (Type II, Model 1916). Production of both the 93 and 1916 models overlapped so it may be difficult to tell what you had originally (a lot of these have mismatched or altered bolts as well for by importers for resale).

Try this website which has serial numbers and some production dates for the different models http://masterton.us/Spanmauhome

Spain was a poor country and after the Spanish American war suffered even more. The 1893 model had the traditional long barrel 29.1 inches which was a holdover from the old blackpowder days. In the early smokeless powder era, inertia and cautiousness led to continuation of these long barrels--e.g. Krags, GEW 98 Mausers, 1889,91.1893, 1896 Mausers, the Long Lee-Enfield and so forth. The U.S. and England went to roughly similar size rifles with the SMLE and the Springfield where short barrelled separate calvary/support carbines versus the long barrelled infantry rifles met in the middle with roughly 24 inch barrels. During WWI, it became apparent that the long barrels weren't that useful in warfare so Spain refurbished some of the 1893 Mausers by cutting down the barrels or rebarrelling in WWI around 1916 with 22 inch barrels and later newer rifles followed the 1916 pattern with the shorter barrels. Spain, however, still made some 1916 Carbines with around 17 inch barrels. In WWII, Spain switched to a large ring Mauser 98 variant and many of the 1893/1916 models were sold postwar or converted to FR7 training rifles to prepare for the CETME rifle perhaps. Others were transferred to the Guardia (a cross between the National Guard and police) and converted to a 7.62 round which stirs controversy today.

A lot of the more recent ones on the market came from the bankruptcy of SAMCO Global Firearm importers which many of these were bottom of the barrel left after the last couple of years in strong firearm sales and I suspect parts rifles assembled out of leftover parted out rifles. Caveat emptor if you are buying sight unseen as the rifle you get may not be shootable.

 

[Captcurt]

boom boom:
This is what many hours of my reading indicates, in general terms. Do you find that any of it summarizes what you described? I typed this and Then read your very detailed, well-informed post.
Small-ring Mausers (designed for 7x57) have the weaker steel receivers (1890s steel). Many were converted to 7.62 NATO, and some became the FR7 carbine.

In contrast, the Large-ring Mauser receivers in 8x57 should be much stronger than the small-ring. And those L. ring 8x57 receivers in a gun with moderate use should be strong enough to handle both 7.62 NATO and modern comm. .308 ammo with a good safety margin, provided head space is safe.
Many large-ring (8x57) Spanish Mausers were converted to the FR8 carbine, but appears identical to the FR7, other than the original bolts' 'turn down' shape.

Please correct anything here which is not accurate. Even more confusion spread because the Spanish 7.62 NATO ammo was designed to be weaker than standard 7.62 NATO, Not because of the FR8's strength (large-ring), but either for use in the weak Small-ring Mausers' receivers, or for soldiers training with their first G-3 military rifles (like the HK-91).

Even with the actions made in Germany the 93 only has 2 locking lugs. The 98 has three. According to Small Arms of the World the author, Ray Bearse, states that, and I quote, "Spanish M93 and the small-ring M95 Mexican/Chilean Mausers should be avoided when selecting a 7mm rifle or action. Not designed for loads in excess of 45,000psi.

Your M93 should be checked, but it is probably fine with the low-pressured factory loads. I would look for a commercial action or a M98 for a build. JMHO.

 

[theotherwaldo]

I have several old rifles that only see reduced loads and cast bullets, sometimes even black powder loads. The National Ordnance 03/a3 is one, the '16 Spanish Mauser in 7.62 CETME is another.

If you want to salvage this as a high-powered rifle I would suggest that you find a donor rifle or barreled receiver to fit your stock and accessories.

 

[boom boom]

boom boom:
This is what many hours of my reading indicates, in general terms. Do you find that any of it summarizes what you described? I typed this and Then read your very detailed, well-informed post.
Small-ring Mausers (designed for 7x57) have the weaker steel receivers (1890s steel). Many were converted to 7.62 NATO, and some became the FR7 carbine.

In contrast, the Large-ring Mauser receivers in 8x57 should be much stronger than the small-ring. And those L. ring 8x57 receivers in a gun with moderate use should be strong enough to handle both 7.62 NATO and modern comm. .308 ammo with a good safety margin, provided head space is safe.
Many large-ring (8x57) Spanish Mausers were converted to the FR8 carbine, but appears identical to the FR7, other than the original bolts' 'turn down' shape.

Please correct anything here which is not accurate. Even more confusion spread because the Spanish 7.62 NATO ammo was designed to be weaker than standard 7.62 NATO, Not because of the FR8's strength (large-ring), but either for use in the weak Small-ring Mausers' receivers, or for soldiers training with their first CETME "G-3" military rifles (like the HK-91).

The large ring Spanish Mauser 98's can take anything that a typical 1930's Mauser can--they still have the hard shell over a softer core but generally better metallurgy and heat treatment as well as design strength. Assuming no cracks, excessive pitting, lug setback, etc., those are fine with 7.62 NATO. The Small Ring Mausers were actually made up to the Spanish Civil War in the 1930s--the Spanish went to the large ring in the midst of WWII (1943) into the post war period.

There is considerable confusion over the 7.62 Cetme round. This is what light I can shed on it. Unemployed German engineers who had experience in developing the German Sturmgewehr assault weapon using roller delayed blowback (see Forgotten Weapons http://www.forgottenweapons.com/last-ditch-innovation-video/ ) This was the genesis of Spain's Type A and early Type B Cetme rifles. Type A, if I recall were experimental models in a variety of calibers. The first production models, early Type B, were in the 7.62 x 51 cartridge form but downloaded with a much lighter bullet (and perhaps powder) to the degree necessary to allow functioning of the delayed roller system and perhaps helping control issues with automatic fire--apparently full bore NATO ammo was too much. The strange thing is that Spain apparently was producing NATO spec 7.62x51 ammo before widespread distribution of the CETME but I do not know what machine guns or other weapons made by the Spanish used. In an earlier THR thread regarding these, I reference a gunboards post which has significant primary source documents regarding production of 7.62 of all sorts ammo by the Spanish in the 1950's. Then, there is the whole Guardia rifle issue which uses converted Mauser 93 and 1916 models to fire apparently 7.62 NATO (not CETME) if you trust their Guardia manual on the rifle in 1967.

It may be that the CETME round was initially produced primarily to get around shortcomings of the original CETME B model and then used generally. By the late B model and subsequent 7.62 caliber models, these rifles could and did use 7.62 NATO. The FR7 and FR8 apparently were the Spanish military's attempt to develop training weapons that used the CETME series sights and of course could use the 7.62 CETME round. There are some strange time discrepancies, lost or missing production records--partially due to the Spanish Civil War. Spain also changed and scrubbed rifle crests and serial numbers when rearsenaled and Spain's relative poverty also caused reuse along with some questionable practices--e.g. lining barrels and chambers in some. Later Franco era secrecy has hampered research into these weapons and then most of the original documents are in Spanish, of course. Spanish small arms in the twentieth century would be a fascinating book if anyone ever undertook the monumental effort.

To sum up, the original small ring Mauser 93 lacks the later safety advances by Mauser 98 design. There is no third lug, the gas handling is inferior, and the receiver was designed around the 7 mm Mauser round including strength and feeding from the magazine and bolt lugs. Many of these 93 rifles were stored, used, and abused, and then converted to a 7.62 round whether CETME or NATO, sometimes using dubious methods like sleeving a barrel. The Mauser method of a hard surface with a soft core does give a safety margin not present in a more brittle receiver if the heat treatment was DONE RIGHT--without testing for hardness of a particular receiver, one cannot know and this rifle was made at first by the Germans at Oberndorf, then by the Spaniards for over thirty years which is a generation in manufacturing processes.

The passive safety measure in a Mauser is that the receiver lug recesses will deform and prevent the bolt from coming back at you--the risk then is that cartridge separation may occur due to excessive headspace introducing a lot of hot gas in a receiver ill equipped to deal with it--e.g. blowups like that National Ordinance rifle Slamfire posted below or hot jets of gas going down the bolt raceway into someone's eye (which is how Peter Mauser reputedly lost eyesight in one eye and redesigned the 98. The Spainiards themselves bored gas escape holes in the left side of the receiver to assist in this event in the 1916 models which indicates a known problem. Now, the deformation may be fast, or may be slow, and some allege that the Spainiards reheat treated the receivers--I do not know. I do know that often re-heat treatment can fail (which is why the U.S. experimented with it but ultimately rejected it) under the best of cases or worse yet make a brittle receiver. Others cite the White Laboratories report that Samco used to sell people on the safety of the 7.62 conversions. Now, handloaders who are knowledgeable can load cast bullits, or download 7.62 loads, reconvert back to 7mm or less such as the original .257 Roberts, and so forth. But if the headspace is excessive, due to lug setback--that receiver should be retired. The rifle might fall into someone's hands who did not know any better and bad things can happen just like to that kid in Slamfire's post. I'm sure that he did not check the internet much to find out about National Ordinance receiver deficiencies.

Can you fire a Spanish Mauser safely--a qualified yes. First, within its original design parameter or below on pressures etc. if the receiver and barrel are in good shape. Second, conversions should have the headspace regularly checked with gages, frequent inspection of the receiver, chamber, and bore, and only known good ammunition should be used preferably loaded on the light side. Old milsurp ammo, careless handloads, etc. can result in a tragedy with these old warhorses. Usually bad accidents occur with a number of preventable actions preceding it. E.g., the receiver and chamber are fine but the barrel is rusty and pitted, a mouse fart cast bullet load sticks one in the barrel and the next round fired blows the rifle sky high. An old bolt with a cracked lug shears off, causes a cartridge separation, and blooey. Firing old milsurp ammo (deterioration of the ammo can lead to changed powder burning rates and cartridges may separate) results in a hot load, blooey. and so forth.

For your health, and safety, learn about these rifles and what they can and can't do from authorities. Me, I'm some guy on the internet with my own opinions and I am naturally cautious-I like my fingers, eyesight, and my face (even if ugly) just the way it is. Other folks will chime in with obvious different opinions--telling you of a 93 Mauser conversion they have or did in .300 Win Mag or some such and it is possible that they have done it and come out all right for now. Think about how many Remington rifles were sold over the decades with that trigger and how many were affected negatively. When the trigger malfunctioned in a some cases combined with other factors, it was devastating, but it was a relatively rare occurrence. If it happened to you or a loved one, the rarity of the event was not much consolation when it was revealed that a relatively cheap fix by Remington could have prevented it.

For that reason, listen to an authority and then make a reasoned decision. Read someone like Jerry Kuhnhausen, a well versed gunsmith (getting rarer), Pat Sweeney, Phil Sharp, Col Brophy, the CMP, some of the old gunsmiths in their manuals, or an acknowledged expert such as John Wall in Mausers on Gunboards Forum, Mike Venturino if you are reloading for these, or an experience milsurp shooter such as Slamfire (who is on multiple forums btw) are worth listening to. For AR's, a different crowd and so on for different firearms.

Be careful out there and stay safe.