Mauser Modelo Chileno 1895 7.62x51 Nato conversions

[Dutchman]

This concerns the 1895 Chilean Mausers that were converted to 7.62x51 Nato. They are unique in the manner they were converted. Until I'd done this apparently nobody in crufflerwapenland knew how this conversion was made manifest. My webpage on this gets a lot of hits and it gets shared by the likes of noted Mauser collector John Wall.

http://dutchman.rebooty.com/1895Chile.html

http://images18.fotki.com/v673/photos/4/28344/8217713/chileno95-vi.jpg

http://images18.fotki.com/v673/photos/4/28344/8217713/siderail-vi.jpg

http://images17.fotki.com/v372/photos/4/28344/8217713/bridge-vi.jpg

http://images54.fotki.com/v563/photos/4/28344/8217713/95notch-vi.jpg

http://images18.fotki.com/v673/photos/4/28344/8217713/95notch2-vi.jpg

[Dutchman]

When I first removed the barrel from the receiver I'd noticed a silver ring around the chamber. It sure looked like silver solder....

I uploaded a much larger photo below.

http://images18.fotki.com/v673/photos/4/28344/8217713/A95-vi.jpg

The areas of the solder joint that have no solder were, IMO, eroded away by flame cutting.

I also noticed a secondary phenomenon out in front of the chamber where the lands are more heavily fouled with copper jacket material. I had wondered about that until I studied on it a while and realized it was caused from overheating of the barrel when the rear sight base was re-soldered on the barrel. That was the only section of barrel that had this degree of copper fouling on the lands. Too high a heat will shrink steel, and in this case, shrink the diameter of the bore. Think about the somewhat increased pressure needed to force that oversize bullet through the neck of the funnel, as it were.

I cut the threads off the receiver ring so the bolt lug races were clearly visible. This is what is known as "lug setback".

http://images52.fotki.com/v728/photos/4/28344/8217713/95ring3-vi.jpg

http://images17.fotki.com/v372/photos/4/28344/8217713/95ring2-vi.jpg

This contrast enhanced image shows a not uncommon malady with some Mausers. Unequal lug contact. There's more wear and setback on the lower lug race.

http://images52.fotki.com/v734/photos/4/28344/8217713/95ring-vi.jpg

Can lug setback be detected with headspace gauges?

Not always.

The reason being -- just before the setback recess there's usually a lip. This lip is at the top of the camming surface as the bolt closes. This can cause a false reading with a headspace gauge in that the bolt will stop turning when it hits the high spot, the lip. Headspace gauges are to be used with a delicate touch, not forced, so that the person gauging may not realize the problem exists.

(this situation can also be applied to 1893/16 Spanish Mausers converted to ~some~ form of 7.62mm)

[StarMetal]

When I first removed the barrel from the receiver I'd noticed a silver ring around the chamber. It sure looked like silver solder....

I uploaded a much larger photo below.

http://images18.fotki.com/v673/photos/4/28344/8217713/A95-vi.jpg

The areas of the solder joint that have no solder were, IMO, eroded away by flame cutting.

I also noticed a secondary phenomenon out in front of the chamber where the lands are more heavily fouled with copper jacket material. I had wondered about that until I studied on it a while and realized it was caused from overheating of the barrel when the rear sight base was re-soldered on the barrel. That was the only section of barrel that had this degree of copper fouling on the lands. Too high a heat will shrink steel, and in this case, shrink the diameter of the bore. Think about the somewhat increased pressure needed to force that oversize bullet through the neck of the funnel, as it were.

I cut the threads off the receiver ring so the bolt lug races were clearly visible. This is what is known as "lug setback".

http://images52.fotki.com/v728/photos/4/28344/8217713/95ring3-vi.jpg

http://images17.fotki.com/v372/photos/4/28344/8217713/95ring2-vi.jpg

This contrast enhanced image shows a not uncommon malady with some Mausers. Unequal lug contact. There's more wear and setback on the lower lug race.

http://images52.fotki.com/v734/photos/4/28344/8217713/95ring-vi.jpg

Can lug setback be detected with headspace gauges?

Not always.

The reason being -- just before the setback recess there's usually a lip. This lip is at the top of the camming surface as the bolt closes. This can cause a false reading with a headspace gauge in that the bolt will stop turning when it hits the high spot, the lip. Headspace gauges are to be used with a delicate touch, not forced, so that the person gauging may not realize the problem exists.

(this situation can also be applied to 1893/16 Spanish Mausers converted to ~some~ form of 7.62mm)

Pretty interesting stuff Dutch. IMO the 308 is too much pressure for that action.

Joe

[Dutchman]

This shows the safety lever interaction with the cocking piece. When the safety is applied it "cams" the cocking piece back and away from the sear. In some Mausers where the safety is difficult or impossible to set this can be remedied by carefully stoning this camming surface on the safety lever and inspecting and possibly stoning the cocking piece if there's any burring present. This sometimes happens with mis-matched parts.

http://images21.fotki.com/v208/photos/4/28344/8217713/b2-vi.jpg

The usual argument is: Them thar Chileno rellenos figured it was ok so it must be safe.

As an expedient procedure for occasional use, maybe, probably. Obviously many of these rifles have survived. But what was safe for Chilean soldiers in 1962 may not be safe for JoeBob, father of 4, in 2009. This rifle above was beyond safe use.

When the same old tired argument about 7.62 Nato versus three-O-eight comes up you need to think about now, not then. What may have been a good and expedient idea then doesn't mean its a good and safe idea now.

This does not apply to the Steyr Model 1912 Mausers converted to 7.62x51 Nato as those rifles are 98 actions and were completely rebarreled, some with new 2 groove 03A3 barrels. The Steyr Model 1912 is a darn good and very strong rifle well suited to about anything you can fit in it.

Dutch

[Bob S]

Dutch:

I have a 1912 long rifle conversion that uses the rebored original barrel with a chamber sleeve. I have had a Lothar Walther barrel to replace that one when I get a roundtuit.

I have a M1912 short rifle that was rebarreled with a US 03A3 barrel. The chamber is noticebly off axis, so one wonders if they even used a pilot on the reamer. It shoots cast stuff "OK", though ... 'bout 3" at 100 yards.

Resp'y,
Bob S.

[Dutchman]

Dutch:

I have a 1912 long rifle conversion that uses the rebored original barrel with a chamber sleeve. I have had a Lothar Walther barrel to replace that one when I get a roundtuit.

I have a M1912 short rifle that was rebarreled with a US 03A3 barrel. The chamber is noticebly off axis, so one wonders if they even used a pilot on the reamer. It shoots cast stuff "OK", though ... 'bout 3" at 100 yards.

Resp'y,
Bob S.

Hi Bob

I have one of the 1912 short rifles with the 2 groove here at the house. Bought it from Century Arms without a bolt for $18. Bright sharp barrel. I haven't really spent any time with it to check it out much other than to see its good enough to play with. It might be my first rebarrel job. I'm sorry I didn't get one of the 7mm long rifles when they were available. They're nice rifles.

Dutch

[mike in co]

gentlemen,
there are two different items in this post.
one, is the 1895 7.72 nato a safe conversion
two, the actual pressures of 7.62x51 nato and 308 win.
and as a reference point the 7x57 mauser pressure limit by the europeans, not saami.

[mike in co]

the original loading, 7 x 57 mauser is
Maximum pressure (C.I.P.) 390.00 MPa (56,565 psi)

please note this is MPa/psi..and not an old cup nor an anemic saami number

[prsman23]

4 year old post resurrected. Record?

[mike in co]

for current 7.62x51 nato the std is EPVAT NAAG-LG/3-SG/1, and MPa is 60191 psi

for current 308 win the std is either saami using Piezo SAAMI and MPa is 62000 psi
or
.................................................c ip using Piezo CIP and MPa is 60191 psi

one must remember that the safety margin is large as a testing point and who knows how large in reality.
both use 25% or more over design for proof pressure...so for one the 1800 psi difference in the two stds is insignificant.
125% of 60191 is 75238...... nearly 15000 psi over design....so the 1800 is pretty insignificant as mentioned.
the 62000 is only 5435 over the 56565 of the original 7 x57 load....this still leaves a safety factor of 10,000 psi from the nato/308 view or if the rifle was truely only safe for 7x57( which i doubt) at 70000 psi, one still has a safety margin of 8-10,000 psi IF one shoots at max all the time.

one need to be very careful with old cup numbers and the newer psi figures. the cup was a guess by deformation and not precise as electronics. the two methods measured pressure at different points so not really comparable.

one would have to presume that the government proof tested the rifles as part of the conversion process.
this si jsut the tech stuff...the numbers
what might be looked at is the difference of the original 7x57 and the the 7.62 nato

[mike in co]

is the 7.62 n 1895 safe to shoot with 308 win ammo ?
in my opinion, yes but i do not know for how long......
with an answer like that i would try to stay in the cast boolits family of shooting.
with jacketed bullets the long bbl does allow for lots of velocity WITHOUT a lot of pressure.

the problem, as dutch has shown, is you the user have no practical way to observe the loss of solder from the insert joint.

i picked one up last year and have yet to fire it...it is scoped with a LER 2-7x AIM 30mm tube......

[mike in co]

sure because i just picked one up, and there is always a lot of mis-information on 7.62 nato and 308 win.
i have been gone longer than you have been a member...lol..i just came back.


4 year old post resurrected. Record?

[prsman23]

Fair enough. I had one for a bit. Never shot it. Mainly because of the original post. It was a beautiful rifle. Had it been in 7mm I would be shooting it today.

[enfieldphile]

For factory ammo shooters, Remington and Federal both produce a reduced, condom load, like a 30/30 in a .308 case. In Fact, Federal uses a flat-point 30/30 bullet.

As for the .308 Vs 7.62 NATO debate. There is alot of debate on the subject. Some say there is no actual pressure difference, just the numbers are different. FACT: the case dimenthions ARE slightly Different. IMHO, there are pressure differences.

In practical terms, these are 100 y/o + rifles. The steel of 100 years ago is inferior to the steels of the 1930's. the steel of the 50's was better yet. The steel of 30 years ago isn't even as good as the steel of today.

Stick to light cast loads in these guns or the Remngton or Federal reduced pressure loads.

I'm just sayin'...

[Larry Gibson]

I've pulled the original 7mm barrels of a few M93 & M95s and most of them exhibited the "lug setback" as pictured from the use of 7x57 military ammunition and not 7.62 NATO or .308W ammunition. The psi (peizo-transducer or strain gauge) of 7x57 milsurp ammo is higher than most believe and quote. From the looks of the non eroded throat of that barrel it wasn't shot with too much 7.76 if any other than perhaps a "proof" load if even that was done. The pictured "lug setback" is atypical of what I found in several M93/95 actions with the 7mm barrel removed.

The real problem with the M95s that were re-lined and then re-chambered to 7.62 NATO is the gas escapes into and erodes the brazing of the chamber insert and the barrel splits. There are numerous examples of this in books, magazine articles and probably on the internet. I do not recommend the use of any loads with these rifles having a re-lined barrel. Has nothing to do with the action but is all about the re-lined barrel.

Larry Gibson