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Old May 8, 2010, 08:40 AM   #1
Famas
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Chamber weld question

Hello - I have a question regarding a bolt-action rifle which I am interested in, and your answers may determine whether or not I buy it or pass it.

It is a military turnbolt, and the seller states that a weld was placed inside the chamber to prevent a cartridge from being loaded into the breach. Precise wording: "Chamber appears to have been welded shut at some time forbidding the chambering of a cartridge".

The bolt appears to be able to open and close without a problem, but my question is, can such weld as this be removed effectively as to restore function (firing), or is it a hopeless cause? I am unware to the extent of the weld, the seller hasn't mentioned if the breech was plugged or not. Can something like this be drilled and reamed away?

Thank you for your input.
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Old May 8, 2010, 08:48 AM   #2
m.p.driver
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You probably could ream or grind it out,but with the heat applied to the barrel from the welding it wouldn't be a good idea.There is no way to know how the barrel was affected.But you might be able to re-barrel it but once again i would question how hot the receiver got.
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Old May 8, 2010, 09:05 AM   #3
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Hello - Thank you for your response. Yes, I was wondering about the heating problem myself. There are tapping/drilling fluids which can be used, though I'm not sure how effective it would be. I imagine they are to protect the drilling bit more than the material being cut. If removing this weld may affect the tempering of the receiver and/or barrel, then perhaps I should not purchase this rifle.
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Old May 8, 2010, 09:15 AM   #4
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If your intent is to in some way return this firearm to shootable status, there is one answer. DON'T do it.
As MP Driver noted, you have no way of knowing how hot the RECEIVER got during the barrel welding process. Therefore, you have no way of knowing what has happened to the heat treating of the receiver, or what parts of the receiver have had their heat treat changed.
A Kaboom of a high powered rifle is not pleasant and can be extremely painful or fatal.
Leave the rifle as a wall hanger. Go to Gunbroker or the equivalent to find good non modified rifle to work with.

Roger
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Old May 8, 2010, 09:16 AM   #5
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I would never trust it as you don't know what damage was done by the welding.
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Old May 8, 2010, 09:32 AM   #6
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In many countries, in order to "deactivate" a fire arm, they drill a hole through the barrel, insert a hardened steel bolt, and then weld barrel and receiver together. Those guns are toast.
If the gun was blocked by some other means, a competent gun smith can probably decide if the obstruction can be removed and/or if the receiver is salvageable. For all it's worth, a chamber cast gone wrong might look like "welded breech" to the next guy. A piece of threaded rod down the throat for sure destroys the barrel, but the single tag weld used to secure it doesn't preclude the receiver from being rebarreled if the gun value justifies it.
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Old May 8, 2010, 06:17 PM   #7
James K
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A lot depends on the gun and the country it is in. Assuming it would be legal to restore the gun to firing condition, it might not be worth it for an old rifle for which there is no ammunition available and would be a wall-hanger in any case. If the rifle is a common one (say a German K.98k) it can be rebarrelled if the receiver was not heated enough to harm the receiver ring.

Whether the weld can be reamed out depends on several factors, including the hardness of the weld itself and, again, how extensive the heating was.

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Old May 8, 2010, 07:01 PM   #8
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"Welded shut" sort of jumps out at me. If that is indeed the case, they got it pretty hot unless they welded a plug in it.
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Old May 8, 2010, 11:25 PM   #9
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I TIG welded and then cut away material.

I wanted to get rid of the case bulges when I shot hot loads in the 40 S&W Glock 22.

I have also done that with 32acp and 9x23mm.

In 44 mag I have done the welded on barrel extension.



Here is a rifle receiver welded on.


Here is another receiver welded on.


Here is a rifle barrel turned into a pistol barrel by welded on a lug for link.


I welded on this AK47 steel scope mount to a 91/30 receiver
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Old May 9, 2010, 08:24 AM   #10
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Just thinking out loud and don't claim to be an expert. But, weren't some of these rifles case hardened? And, the question being that if you get it hot enough you really have no idea what hardness you will end up with and how brittle you could make it?
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Old May 9, 2010, 08:45 AM   #11
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Steel becomes annealed at 1300 Deg. F. and melts at around 2000 Deg . depending on composition . I wouldn't consider it for anything but a parts gun !
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Old May 9, 2010, 11:18 AM   #12
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The Russian is done O.K., it looks like the aluminum part is screwed in. The side mount is O.K. also. Russians are case hardened, but if you stay away from stress points and keep the stress points cool (like welding bolt handles) you will be fine. I filled a split bridge on a Russian and changed the bolt with no material problems. The barrels are another story. The pistol rounds are low pressure and you will probably get away with it. Barrels above .22 on a rifle are almost always 4140. Weld on that and it will go to 60 Rockwell on the C scale. This is extremely brittle where pressure is concerned. Some older rifles had receivers that were made out of 4140, but rifles like Russians and Mausers used low grade steel and can be welded on if you stay away from the pressure areas.
Anybody know what 99 Savage receivers were made of? I never found one crappy enough to cut up and check out.
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Old May 10, 2010, 10:30 AM   #13
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CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.


That 40 sw chamber above is ~0.1" thick on the sides.

I have run 15.5 gr 800X 200 gr in that 40sw that I TIG welded to get full case support.
That is more than a double load for 40sw and a max load for 44 mag, but the 40 has less case volume, so the pressure goes much higher.

I have bought hundreds of guns, just to overload them and see what happens.
What have I learned?
Most of what people think is wrong.
They fall into a mode of "What was it designed for?"
A much better question would be, "How thick is the metal?"
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Old May 10, 2010, 12:26 PM   #14
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An even better question is "What kind of metal is it?"
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Old May 10, 2010, 01:13 PM   #15
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Case support and barrel strength are only some of the equation when loading very "hot" for an auto pistol. Other concerns are battering or even stripping the locking lugs, battering the frame point which stops the slide, and damaging the extractor and ejector. Of course if one is engaged in experiments that involve deliberate destruction of the pistol, that doesn't matter, but most folks don't want to do that.

Jim
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Old May 10, 2010, 07:53 PM   #16
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In May 2000, after I worked up past the 460 Rowland level in a 20 ounce Patriot Arms 45acp, I was painfully aware of the slide slamming into the frame.

I wrote this in June of 2000:
http://groups.google.com/group/rec.g...413dedc2d3bf2e

Quote:
For quite a few pistols, I have measured the minimum amount of powder
necessary to get a semi auto to cycle with the stock spring and also the
amount of powder with the heaviest spring available. What I have found
is that only a fraction of the momentum of the bullet is reflected in
the momentum of the slide and barrel. It seems that most of the recoil
is transferred to the hand before the bullet leaves the barrel.

http://www.m1911.org/

click on the pistol
click on technical issues
click on recoil spring selection tips by Bill Wilson
"As a rule of thumb, you should use the heaviest recoil spring possible,
which does not interfere with the pistol functioning."

I use AA#5 as you can see it has a very predictable powder to pressure
ratio
1) 45 acp 185 gr 1100 fps 10.2 gr AA#5 18,000 psi
2) 45 acp +P 1200 fps 10.8 gr AA#5 21,700 psi
3) 45 Super 1312 fps 12.4 gr AA#5 28,000 cup
4) 460 Rowland 1500 fps 14.5 gr AA#5 38,800 cup

Example:
Patriot 45acp
http://www.republicarmsinc.com/

15 pound to start and 42 pound spring at the rear [home made spring
assembly], is just right for 10.3 gr of AA#5. That is, it is just enough
powder to keep the Patriot from jamming with that spring.

The bullet leaves the gun at 1100 fps.
The bullet weighs 185gr = 185/7000 = .026 Lb.
The slide weighs .5 Lb.
The barrel weighs .1 Lb.
The spring is 15 Lb to start.
The spring is 42 lb at back.

The momentum of the bullet equals the momentum of the slide and barrel.
[1100][.026]=V[.5+.1}
V=47.7 feet per sec
Velocity of slide and barrel = velocity of slide
Energy of slide = .5mVV= one half mass velocity squared
Es=.5[mass of .5 pounds][47.7][47.7]
Mass = [wieght]/gravity= .5/32.2=.0155
Es=.5[.0155][47.7][47.7]=17.64 foot pounds of energy

The energy required to pull back the slide = [force][ distance]
Force = average force = [15+42]/2 = 28.5 pounds force
distance = 1.656"=1.656/12=.138 feet of slide stroke
Eslide = [28.5][.138]=3.93 foot pounds

BUT WAIT A MINUTE! 17.64 DOES NOT EQUAL 3.93!

Not all of the bullet momentum went into the slide and barrel.
Some of it accelerated the hand.
Only 3.933/17.64= 22% went into the slide and barrel.

What does this mean to someone who wants to calculate the spring needed
for a semi auto pistol?
Heavy firm hands need stiffer springs than soft light hands and there is
no good way to measure how light and soft one's hand is.
So, you cannot accurately calculate the spring you need.

However, a CZ52 9mm pistol takes 4.7 gr AA#5 to cycle with a 125 gr .357
bullet. Put in a Wolff +10% spring and it takes 5.3 gr AA#5 to cycle. So
you can calculate spring requirements over a small region of already
known spring requirements.

The 22% finagle factor [above] will go up for heavier slides with
lighter springs. The above example is an extreme case of light slide and
heavy spring. The numbers are usually around 30~33%.

Never say "limp wristing" again. Say, "If the gun jams, get a lighter
spring. If the slide slams the frame, get a heavier spring."
Clark
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Old May 10, 2010, 08:11 PM   #17
Bill DeShivs
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There is a lot of misinformation in this thread.

"Case hardening" involves carburizing the surface of a soft steel. It only affects the surface, is extremely hard and wear resistant.

4140 steel will not go to 60 RC. There is not enough carbon in 4140 (.4%) to get that hard. 4140 is a carbon steel that requires quenching in water or oil to harden. It will not air-harden after welding.

Steel begins to soften, from it's fully hardened state, at around 400 degrees. Complete annealing occurs arounf 1400 degrees.
I'm not an expert on gun heat treating, but it has been my experience that a lot of gun parts are not hardened at all. I do know a little bit about carbon steel, though.
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Old May 10, 2010, 11:30 PM   #18
Clark
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Bill,
I don't know much about metallurgy, but it looks like you are right about that:
http://www.eng-tips.com/faqs.cfm?fid=1290

I read in Oct 2000 Design News about the Ruger 454 with specialty stainless that will do 260 ksi at peak aging.
I think that is ~ 53 on the C scale.

I buy rods of 4140 from MSC that is pre hardened to RC28, still soft enough that I can machine into gun parts.

I think my father designed springs to return the M55 to battery with 4140.

http://www.thefabricator.com/article...d-alloy-steels

http://www.interlloy.com.au/data_she..._bar/4140.html

At .4% Carbon, 4140 would be categorized as medium.
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Old May 11, 2010, 07:22 AM   #19
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Now there is even more misinformation. 4140 will go to 60 Rockwell with oil quench and pass that with water quench. With proper quenching oil it will go to about 57-58 RC, with sulphur oil slightly higher. 4140 will air harden when welded, especially arc welded. To what degree it hardens is a crap shoot. Anyone that ever welded a bolt handle on an Arisaka can tell you that. That pre-hard 4140 you buy was already drawn back to 28-30 RC. Same with gun barrels.
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Old May 11, 2010, 07:57 AM   #20
Bill DeShivs
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I doubt 4140 will go to 60RC.
We knifemakers use steel with 1% or better carbon, and 60 is near the upper hardness when tempered. 1095 will go to the 70s when quenched.
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Old May 11, 2010, 11:12 AM   #21
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Throw a piece in water. Even 58 RC is hard, and that is standard before tempering. 1095 is saltwater quench if I remember correctly. Quenching media has a lot to do with it. 4140 will easily go to 57-58RC in quenching oil. If you have a torch, try a small piece. Gun parts are drawn back or they are too brittle.
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Old May 11, 2010, 12:50 PM   #22
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You guys know more than me, but I did learn from those sites I linked that quenching only goes so deep. That makes it harder on the surface and softer in side.

Back in the early 80s I built a solar home and read about Trombe walls with thermal phase shift of hours.
Evidently the phase shift delay and averaging causes the interior of thick steel to not quench quickly, allowing the Carbon molecules to migrate out of and not get trapped in the Iron matrix.
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Old May 11, 2010, 03:31 PM   #23
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Nobody is taking sides here,good to learn new stuff. I agree with the Russian weld jobs, I welded a piece in the bridge of one and changed the bolt handle. You probably should use some kind of heat sink around the receiver ring, but I doubt if it affected it anyway. I would be careful what type of material I am welding on, it really does make a difference. You should have been around for the '03 Springfield thread, that was fun.
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Old May 11, 2010, 11:10 PM   #24
Famas
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Thank you all for your input, I really appreciate it. A lot of good information here. Given the information received here, I've decided it would be wiser to not purchase the rifle I was interested in ( a French Berthier, a rare m1916/m34 conversion). Maybe one day I will find another which hasn't been demilitarized. Thanks again to all for your help.
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Old May 12, 2010, 08:59 AM   #25
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I think you made the right decision to pass on the rifle.

But, all of the quenching/hardening info aside, here's something else to consinder. This may be useful for anyone considering one of the many de-milled Springfields on the market here in the US, or any other welded gun for that matter.

Assuming everything else is correct and safe, i.e. no cut receiver ring etc., if actual weld material has made it into the chamber, it may not be a simple matter just to ream it out.

IF the filler metal is harder than the chamber walls, it will have a tendency to divert the reamer into the softer metal. This is the same principle we use when setting a cement kick-off plug to drill a horizontal segment of an oil well.

Without a STIFF setup, you could easily cut an off-center or out of round chamber. Often, taking the gun to a machine shop or gunsmith with capeable equipment will cost more than having just bout a usable specimen to start with.
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