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Specific Question on Mauser Heat Treating...
Specific Question on Mauser Heat Treating...
Okay-
I've read the best posts in the archives, sent actions out to be hardened, so this is a very specific question.
If someone told you they had a FN Mauser bolt that tested 68 on the Rockwell C scale, what would you do/think?
Thanks,
flaco
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This FN bolt failure might be of interest to you.
http://forums.accuratereloadin...1043/m/287107765/p/2Bolt: Rc48 surface hardness.
Receiver: Rc55 surface hardness, Rc36-38 core.
28 May 2011, 10:46
kcstottTo damn hard.
Action are supposed to be about 10 point lower in hardness then the bolt.
Bolt should be around 50Rc and action should be around 40Rc
68Rc is ready to shatter if dropped kinda hardness
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
28 May 2011, 15:03
tin canquote:
Originally posted by kcstott:
To damn hard...
...68Rc is ready to shatter if dropped kinda hardness
I'm an amateur, but agreed- that's about 7 points past the hardest knife edge I've encountered.
Following up a bit on Trax post above:
http://forums.accuratereloadin...=276106085#27610608528 May 2011, 18:48
kcstottHigh Speed Steel tool bits for the lathe are rated less then that
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
So.
Do you suspect operator error in Rockwell testing? The conventional wisdom is that all Mausers are carburized to a very shallow depth, and that it's almost impossible to hardness test them accurately.
If the reading is correct, can one assume that too hard or not, it's only a small surface layer, and the inner softness will prevent catastrophic failure?
Do you advise the owner to have the whole action treated?
Do you advise him to throw it away?
Do you advise him not to worry about it at all?
flaco
28 May 2011, 21:37
kcstottBecause the reading was extremely high I would suspect a miss reading. misuse of the tester depending on who did the testing.
I would ask for clarification.
When I was a tool maker paid position. I had to train our QC dept on how to properly set up and use a rockwell tester. Lets just say that if you are not familiar with the finer points of making a precision measurement then you need to find someone who is. I won't go into all the particulars here but everything must be perfectly clean with no burrs or dirt or dust getting between the mating surfaces on the test table. As you pull on the lever to release the weights do so slowly and when you reset the weights to take the reading again do so slowly.
We had one lady jerk the handle like flushing the toilet and it would throw the reading 20 points. Not being on a level stable table is another problem, or in a temperature controlled room. All these things and more can cause a very large miss read
Now I'm not a mauser expert as some here are. But I remember reading somewhere that some mauser blots are thru hardened. being made from a different material then the action. I don't know and would not state that as fact until I found out for sure. I may be getting that confused with the GMR or MRC
Either way if the bolt is case hardened and measure 68 points then either the case is to deep and to hard (like the sound of that on other subjects) or the test was inaccurate.
If the bolt is thru hardened then either the bolt is to hard or the reading is inaccurate.
In either case I would have the bolt and action retested by a facility that has traceable standards or just sent the whole thing off to be retreated with the proper specs being followed.
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
A piece of REX 95 tool high steel rockwells at 64RC. I think that MoMax is about 66 and Tantung G is about 67. These are hand ground tool steels intended to cut other steels. The readings are way too hard for a rifle bolt or receiver.
As a comparison a common smooth file such as made by Simmons is also 67 Rockwell.
I have Rockwell Tested many quality knife blades out of curiosity. They are very boring.
They are almost always RC55. That includes Western, Buck, CRKT, SOG (a Tomcat no less).
A bolt should probably RC in the high 40s and the receiver in the low 40s when through hardened steels are used.
quote:
Originally posted by flaco:
So.
Do you suspect operator error in Rockwell testing? The conventional wisdom is that all Mausers are carburized to a very shallow depth, and that it's almost impossible to hardness test them accurately.
If the reading is correct, can one assume that too hard or not, it's only a small surface layer, and the inner softness will prevent catastrophic failure?
Assuming the test was done properly and it was done on a C scale, not converted from a lighter load, it either has a very deep case or hard metal beneath so as to support the 150 kg load. Dangerous at best. Something is seriously wrong with the metallurgy of that bolt. Numbers like 68 C have practically zero ductility. Even S7, a shock resistant use tool steel, is not used at that hardness.
Do you advise the owner to have the whole action treated?
I would advise following kcstott's advice. Get it checked correctly and go from there. I wish I had the ffl that would allow you to ship the bolt to me. I have many types of hardness testers at work and many years experience using them. And if it is this hard, and he wants to get it redone, the carburize depth needs to figured out. Tempering / annealing will not remove the layer - only soften it. Some thin areas may be cased completely through their cross section.
Do you advise him to throw it away?
Do you advise him not to worry about it at all?
I'd advise him not to drop it on anything harder than a pillow!
flaco
29 May 2011, 22:48
Mike_Dettorrewalnut,
you don't need an ffl to have a bolt shipped to you. A bolt is not a gun.
MikeLegistine actu quod scripsi?
Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.
What I have learned on AR, since 2001:
1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken.
2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps.
3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges.
4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down.
5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine.
6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle.
7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions.
8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA.
9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not.
10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact.
11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores.
12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence.
13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances.
Mike, thanks I didn't know that. I thought recvr, bolt = ffl, barrel, bottom metal + stock no problem.
Flaco, send me a PM if I can help. I have an Instron 2000 Twin that does A,B,C, Superficial HR15, 30 + 45 N along with some older (50+ yrs) Wilsons that do B,C and Superficial as back-ups. I'm in charge of keeping them calibrated and having outside calibrations scheduled. I also have a Tukon Micro-hardness in Knoop in case your friend wants it sectioned, take that as destroyed, to have a very accurate idea as to what is up with it. That is obviously a last resort and good for info only. I have a variety of anvils and can check almost all areas of a bolt. KCSTOTT is absolutely correct when he says the specimen must be clean, held firmly, and especially with the light load Superficial, the surface can not have scratches where the diamond touches down.
30 May 2011, 03:30
BlacktailerOthers may correct me but IIRC as long as the ownership of the firearm is not changing, an FFL is not required. For instance if I need to send my rifle to a gunsmith to do some work on it, he does not have to have an FFL to receive it or send it back to me. So you could send the entire rifle to someone else for testing as long as it didn't violate any local laws and you are not selling him the rifle.
Have gun- Will travel
The value of a trophy is computed directly in terms of personal investment in its acquisition. Robert Ruark
30 May 2011, 04:54
craigsterHe has to have an FFL if the firearm comes into his shop/possesion. It has to be logged into, and out of, his bound book. This is not the case if the work is an "on the spot, while you wait" repair or adjustment. It makes no difference if there is not going to be a change in ownership.
30 May 2011, 06:14
ramrod340quote:
He has to have an FFL if the firearm comes into his shop/possesion. It has to be logged into, and out of, his bound book. This is not the case if the work is an "on the spot, while you wait" repair or adjustment. It makes no difference if there is not going to be a change in ownership.
+1
I sure there are many "gunsmiths
" that function without an ffl. Just cause they do doesn't make it right.
As usual just my $.02
Paul K
30 May 2011, 11:15
kcstottquote:
Originally posted by ramrod340:
quote:
He has to have an FFL if the firearm comes into his shop/possesion. It has to be logged into, and out of, his bound book. This is not the case if the work is an "on the spot, while you wait" repair or adjustment. It makes no difference if there is not going to be a change in ownership.
+1
I sure there are many "gunsmiths
" that function without an ffl. Just cause they do doesn't make it right.
++1
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
quote:
Originally posted by kcstott:
quote:
Originally posted by ramrod340:
quote:
He has to have an FFL if the firearm comes into his shop/possesion. It has to be logged into, and out of, his bound book. This is not the case if the work is an "on the spot, while you wait" repair or adjustment. It makes no difference if there is not going to be a change in ownership.
+1
I sure there are many "gunsmiths
" that function without an ffl. Just cause they do doesn't make it right.
++1
There are many with an FFL and that does not make it right either.....
Craigsters post is the what was explained to me. The local company that does our Hot Black Oxide said I could bring a barreled action in for B.O. and as long as I wait for it and leave the same day, no paper. They do work for S&W but that stuff gets logged in.
30 May 2011, 20:04
BlacktailerYes that's all true but my understanding was if I am sending a rifle to Mike to do some load development for me and he is not an FFL holder and is not "in the business" (no money is changing hands) and after the load development he is sending my rifle back to me, then neither one of us has to have an FFL as long as no local ordinances are being violated. Or is this not correct?
Have gun- Will travel
The value of a trophy is computed directly in terms of personal investment in its acquisition. Robert Ruark
30 May 2011, 20:39
ramrod340quote:
The local company that does our Hot Black Oxide said I could bring a barreled action in for B.O. and as long as I wait for it and leave the same day, no paper
Since you are there the firearm is never leaves your possession. Leave it there and they by law need to log it in just like they do the S&W work.
When I was bluing I did Class 3 parts that way as well. The owner need to be present.
No way am I trying to say tha just because you have and FFL you are a gunsmith. Just that the the ATF considers you a gunsmith and requires an FFL if you take in someones firearm to work on it and it leaves their possession. I would never try to assume what the AFT is going to think or do.
As usual just my $.02
Paul K
30 May 2011, 20:48
ramrod340quote:
Yes that's all true but my understanding was if I am sending a rifle to Mike to do some load development for me and he is not an FFL holder and is not "in the business" (no money is changing hands) and after the load development he is sending my rifle back to me, then neither one of us has to have an FFL as long as no local ordinances are being violated. Or is this not correct?
Here is the NRA quick and dirty comments.
http://www.nraila.org/GunLaws/Federal/Read.aspx?id=60IN theory I believe you are correct. However if the ATF ever got involved on your buddies end he would have to replain and convince them he wasn't operating as a Smith under the ATF regs.
Within most states you could simply sell it back and forth on paper and ship it.
For the 15 or so years I did load development for others it was always under my ffl.
As usual just my $.02
Paul K
30 May 2011, 21:05
kcstottATF also allows you to "loan" a firearm to anyone you choose so long as that person is not precluded from possessing a firearm. Granted in an investigation all the details will come out. I'm not condoning anything illegal and our government can be completely un forgiving in matters such as these so just be careful what you do.
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
30 May 2011, 21:12
BlacktailerI'm sure you don't mean to imply that the ATF is anything but benevolent.
Have gun- Will travel
The value of a trophy is computed directly in terms of personal investment in its acquisition. Robert Ruark
30 May 2011, 21:56
Fal GruntTo add another point to the discussion. Both heat treating facilities I know of (Blanch/Pacmet) do not have FFL's.
I have asked this type of question to my ATF agent a number of times and they will not give me clarification on paper. Course, they also want me to pay excise tax for "manufacturing" firearms but will not let me serialize them.
I would not be concerned about sending an action to a test facility on a one time basis. Remember, regulation is a function of taxation. They cannot have their hand in your pocket if they do not follow you everywhere you go.
Nathaniel Myers
Myers Arms LLC
nathaniel@myersarms.com
www.myersarms.comFollow us on Instagram and YouTube
I buy Mauser actions, parts, micrometers, tools, calipers, etc. Specifically looking for pre-WWII Mauser tools.
30 May 2011, 22:46
kcstottquote:
Originally posted by Blacktailer:
I'm sure you don't mean to imply that the ATF is anything but benevolent.
You bet
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
31 May 2011, 01:21
craigsterIf Pacmet and Blanchard are not FFL holders there must be a BATF regulation that exempts them from what they do.
31 May 2011, 01:51
kcstottOr they just don't give a shit. We have a black oxide shop in our area does the same thing. They just don't care
www.KLStottlemyer.comDeport the Homeless and Give the Illegals citizenship. AT LEAST THE ILLEGALS WILL WORK
01 June 2011, 05:09
farbedoFlaco,
Just to add my 2 cents. Don't use it as is. You have 2 choices: get a new bolt (readily available and cheap), or check the hardness and have it corrected.
An Rc reading of 68 is only possible at a carbon content of around 1.0%. This is only possible in the case layer itself. Maximum obtainable hardness is directly a function of carbon content. So the base metal can't get this hard unless you add carbon to it.
As the other folks have speculated, the reading is probably bogus. The other possibilities as stated are a through hardened bolt, or a case that is excessively thick.
I would tend to think excessively thick case. Bolts are smaller, and heat faster than receivers, so they take a deeper layer if carburized in the same cycle.
Retesting it is appropriate. If it tests high again, it can be tempered into the proper range. It need not go through a full heat treat again, and it definitely should NOT be carburized again.
To temper it would take a controlled furnace at 450F and after an hour check the hardness, then temper another 30 minutes, and check again, repeat until you are in the mid 40's. According to Kuhnhausen. In my experience with heat treating (steel toe caps, drive axles, gears, plow discs), this is a good range for impact toughness. A good heat treat shop should be able to temper the bolt without issue. Tempering will also be referred to as drawing. Some shops use one term, others use both.
Jeremy