Safe Practice to Consider

Many of us including myself in the past have taken our iron sights off when we mounted a scope. We felt leaving those threaded sight holes on the barrel open because they would not be an issue. Well they can pose a problem if left open. The screws actually re-enforce the integrity of the barrel. A good practice is to find and fill these holes with a set screw that sits flush with the barrel if looks is what you are after. Until you find these screws at least put the sight screws back in until you do.

Having seen numerous pictures of barrel ruptures especially some with the 10ML-II one split of the barrel always seem to run through the rear screw hole. Coincidence, I don’t think so.

This picture is not to discourage anyone owning a 10ML-II because no firearm is infallible when the wrong or uneducated person operates it.

Attachment 28123


Ed

This is nonsense. That picture clearly shows the bulge right in front of the charge which indicates either an over charge, improper bullet seat or possible obstruction. Find me some credible examples of untampered/modified screw holes contributing to similar failures in any other firearm. Do you have any idea how many firearms are fired everyday with exactly the "threat" you dreamed up? Have you ever read a disclaimer from any firearm manufacturer advising of this risk? There is also a split under the barrel where there is no screw hole....:ashamed:
Have you ever heard of an action failing because it was drilled to mount a scope? Trust me that action is under extreme stress at ignition.

I see what you getting at Ed...but...I wonder if the integrity is not lost when they drill the blind hole. Since a screw is not bonded to the barrel, we could say it's free floating in the threads, I don't think it would be returning any integrity to the barrel itself. I would think you'd need to fill the hole with a bonding epoxy to offer any return to the stability in that area.

Mind you the screws would offer protection from moisture migrating into the hole causing further structural damage if the holes were not plugged, so yes I would not leave them open.

add: Ed..just ignore the troll in the room :)

Do you really think that epoxy becomes a molecular part of the smelting process? Do you really think a stainless steel barrel like this blown up Savage ML 10 suffered a catastrophic failure from rust? There are millions of severely pitted firearms that are fired safely every day. There are millions of firearms that have ports in the barrel to cycle actions. You people need to get a grip.

Actually no. What you people need to admit is that the Savage ML10 is not to be played with by amateurs.

I don't know what caused the barrel to rupture in the example Ed provided and I cannot say where the barrel failed exactly. But I do know of several examples of a barrel bulge or ring that has occurred with the savage muzzleloaders and every time the ring was in the area of the rear sight, maybe that could be a indication of the potential problem. It doesn't take a rocket scientist to realize there is less metal in the barrel once the sight hole is drilled thereby making it more vulnerable there.

My question would be. Why bother removing the irons if they don't interfere with the scope?

I can see what you are getting at though Ed. I'm not convinced the hole is causing a weak spot that will cause a barrel blowout under proper loading conditions but rather a path of least resistance scenario when the blowout is inevitable.

Quote:

---

Originally Posted by smokeeter

I don't know what caused the barrel to rupture in the example Ed provided and I cannot say where the barrel failed exactly. But I do know of several examples of a barrel bulge or ring that has occurred with the savage muzzleloaders and every time the ring was in the area of the rear sight, maybe that could be a indication of the potential problem. It doesn't take a rocket scientist to realize there is less metal in the barrel once the sight hole is drilled thereby making it more vulnerable there.

---

If it were that simplistic do you not think that the design would not have been changed? There are multiple lawsuits involving millions of dollars over this. Lawyers and engineers squaring off in court over money. Look at that picture closely. The peak of the bulge ( the failure point) is actually behind the screw hole. You people are not only misinformed but probably dangerous to be around.
You people realize that barrels are rechambered and many times rebored completely which removes a hell of a lot more metal than a screw hole yet this doesn't cause failures. This gun was obstructed, wake up!

Quote:

---

Originally Posted by oaknut

rather a path of least resistance scenario when the blowout is inevitable.

---

that's it exactly...

I still want a 10ML someday and when I do get one I am sticking to the recomended loads. I would like to keep all my fingers & eyes...

I take my iron sights off because they look dumb when it has a scope on it. :)

LOL

Quote:

---

Originally Posted by bellerivercrossbowhunter

I still want a 10ML someday and when I do get one I am sticking to the recomended loads. I would like to keep all my fingers & eyes...

---

Really it's no different than the thousands of guys that re-load their own CF ammo. Some guys are happy to buy what CT sells off the shelf for their gun and nothing wrong with that. Some enthusiast like to re-load their own ammo so they can maximize on the performance of the bullet they want to shoot. The inherent danger is mitigated with experience and education.

Fortunately I was able to leave my front sight and rear sights on my ML ( the Shotgun scope mounts behind the rear sight) just so I have a back up in case I damage my scope. I can take it off and use the fibre sights.

Terrym

Ah the wounded poster seeking revenge with trying to discredit.
You don’t even know what I do for a living and part of this is to assist engineers with their analyses for metal structural failure with NDT. Usually NDT is used to find conditions before a failure but can also assist in the evaluation of a failure.
You’ve already made an assumption of the failure and you aren’t even an engineer. Nor do you have a clue in this area. I don’t see you displaying any credibility here at all.
I’m no engineer but know how to find characteristics of a failure that an engineer seeks for evaluation.

MikePal

Yes the hole is considered as a weak point for two reasons.
One it is the thinnest area of solid material.
Two because of the stress riser condition where sharp geometrical change occurs in the metal such as a hole and threading does.
By plugging this hole with a threaded body you add re-enforcement again and reduce the bore pressure flexing attacking this weak area.

In case you are interested in the double split I approach a welding engineer who was also conversed in metallurgy with this phenomenon. His explanation was that when a barrel which is like a pressurized pipe begins to split the strongest area of stress would be approximately 180 degrees from the split and there would usually generate another tear. Depending on the material it could cause additional tearing and not limited to 2-splits.

Also the highest point of a rupture doesn’t always mean it started there but where the strongest pressure was felt.
I have no reason to doubt his years of training and experience.


Ed

Quote:

---

Originally Posted by ET1

Two because of the stress riser condition where sharp geometrical change occurs in the metal such as a hole and threading does.
By plugging this hole with a threaded body you add re-enforcement again and reduce the bore pressure flexing attacking this weak area.

---

That actually make sense, crudely worded..the screw allows for the transfer of the flex.

All round, best to plug the hole for numerous reasons :)

Quote:

---

Originally Posted by ET1

In case you are interested in the double split I approach a welding engineer who was also conversed in metallurgy with this phenomenon. His explanation was that when a barrel which is like a pressurized pipe begins to split the strongest area of stress would be approximately 180 degrees from the split and there would usually generate another tear. Depending on the material it could cause additional tearing and not limited to 2-splits.

Ed

---

I've never taken real note on barrel failures; when they split, I call them banana peel, is it predominantly 2 or 3 sections peeling back ?

edit add: Ed..I just re-watched that video I posted few days back....good example of the barrel failure with obstructions. I noticed the last one he did with the obstruction in the end (under the front sight) the barrel split into 4. It's hard to see where the splits are initiating/occurring.

https://www.youtube.com/watch?v=gmsBF6CXs18

Quote:

---

Originally Posted by MikePal

Mind you the screws would offer protection from moisture migrating into the hole causing further structural damage if the holes were not plugged, so yes I would not leave them open.

---

MikePal

I fully agree that the holes should be protected from full exposure to the elements.
This would be a good additional reason to plug them.


Ed

Interesting....I googled the subject but was unable to find a scientific paper as to why a barrel is more prone to banana peeling versus exploding into shrapnel like a grenade (good thing they don't) when the powder charge encounters an obstruction and something must give way. My first thought was that the rifling somehow had something to do with it but that does not make any sense as it is a twist and the peel is linear. Also, I did witness a shotgun peeling with a muzzle plugged with mud. No rifling there! Can anyone provide a valid explanation?

Quote:

---

Originally Posted by ET1

Terrym

I’m no engineer but know how to find characteristics of a failure that an engineer seeks for evaluation.


Ed

---

I'm no engineer either and the fact you deal with them doesn't really impress me. We consult with our lab routinely and it is staffed with Phd's and we deal with compressive strength and shear strength data for most of our products. So, none of this makes me an expert either.
What you haven't provided is a single disclaimer from any firearms manufacturer, barrel manufacturer, rifle sight manufacturer, to support your theory that drilled and tapped screw holes weaken a barrel to the point of failure. Interestingly you use a Savage ML10 to support your theory. That picture and many others have been around for a while and the screw holes are not ever mentioned as part of the law suits. Some barrels have the rear sights dove tailed into the barrel which removes an enormous amount of material compared to a screw hole yet we have never heard of this practice being potentially dangerous. Rifle actions are almost universally drilled and tapped for screw holes yet you don't hear about failures in actions and everybody knows how much the action absorbs pressure. Every single photograph I have ever seen of a blown up Savage ML10 has a failure of the barrel in front of the charge yet the breech is actually a hole and plug only held by threads but they never seem to fail. Also it has been proven that many of the owners of these catastrophic failures of Savage ML10's interestingly suffered no injury yet the damage of the gun should have caused serious injury. Do you think maybe they expected or intentionally wanted a blowup for litigation purposes?
Anyway, find me a gun manufacturer to substantiate your theory that screw holes can cause a rifle to fail.

The pressure is going to push through the least restrictive path, although the screw hole may be a stress riser putting a screw back in the hole would not change how the barrel would react. That being said, if you do not fill it and there is corrosion that would effect things a lot more than just having the screw hole there. With how these barrels are proofed the screw hole would not be the cause of the initial rupture but may end up in the path of the split due to the nature of a slightly weaker zone in the metal. Rifle barrels do seem to split on a twist, which makes sense with the rifling and the shotgun barrels opening up like a banana makes sense as well due to the consistency of the steel, since there is an obstruction in the barrel the pressure spikes and since all parts of the steel barrel are the same it will cause the rupture to be essentially uniform. I would not worry about your savage blowing up due to a screw hole not being filled, I would worry about putting a BP volume load of smokeless in the barrel, which was probably what caused this to happen.

Barrels will not shatter due to the nature of steel, it is not brittle. Steel fails by tearing, either by excessive force on an area or over time (fatigue). The great thing about steel is that you can build it thick enough to overcome both of these conditions, not so with aluminum, fatigue is always present in aluminum. Heating of the barrel can cause changes to the material as well, brazing on a sight, drilling holes and tapping all cause heat and if done too quickly and building up too much heat can change the material and weaken it is not treated properly afterwards.

Impact

I can only provide one plausible explanation from reasoning.
When we say hardening of barrel metal it is not super hardened. The more it is hardened the more brittle it would be if failure occurs. The level of hardness appears to allow it to keep some of its malleable properties to prevent fragmentation yet hold higher pressure than it would in its normal state of hardness.


Ed

Quote:

---

Originally Posted by Fox

The pressure is going to push through the least restrictive path, although the screw hole may be a stress riser putting a screw back in the hole would not change how the barrel would react. That being said, if you do not fill it and there is corrosion that would effect things a lot more than just having the screw hole there. With how these barrels are proofed the screw hole would not be the cause of the initial rupture but may end up in the path of the split due to the nature of a slightly weaker zone in the metal. Rifle barrels do seem to split on a twist, which makes sense with the rifling and the shotgun barrels opening up like a banana makes sense as well due to the consistency of the steel, since there is an obstruction in the barrel the pressure spikes and since all parts of the steel barrel are the same it will cause the rupture to be essentially uniform. I would not worry about your savage blowing up due to a screw hole not being filled, I would worry about putting a BP volume load of smokeless in the barrel, which was probably what caused this to happen.

Barrels will not shatter due to the nature of steel, it is not brittle. Steel fails by tearing, either by excessive force on an area or over time (fatigue). The great thing about steel is that you can build it thick enough to overcome both of these conditions, not so with aluminum, fatigue is always present in aluminum. Heating of the barrel can cause changes to the material as well, brazing on a sight, drilling holes and tapping all cause heat and if done too quickly and building up too much heat can change the material and weaken it is not treated properly afterwards.

---

Very informative post, you seem to have expertise here. Getting back to the rust thing though, this example shown as evidence is a stainless steel barrel. What do you think are the odds of rust in a screw hole being sufficient to cause such a failure?

Terrym

My dealing with engineers and NDT training sure gives me more knowledge and understanding to work with metals.
I see you have trouble reading English because I never stated that drilled and threaded holes are the cause of failure. What I’m saying is to help avoid the possibility of the weakest area becoming an issue you can help ensure its integrity by keeping the thread hole filled with a screw.

Unlike you I make no claim to state where the failure originated because I’m not an engineer. You seem to have visions of being one to make certain evaluations.
For what reason are you mentioning action screws that usually are not exposed to bore pressure like sight screws?
Is this a diversionary tactic of including a non relevant condition.
If you replace removed material with additional of material like your rear dovetail sight where is the loss of material like an empty sight screw hole?
That was a lousy example.

Your welcome to try and impress others with your knowledge because the impression you have left with me is the lack thereof. Hey spout away if this makes you happy.


Ed

Quote:

---

Originally Posted by terrym

Very informative post, you seem to have expertise here. Getting back to the rust thing though, this example shown as evidence is a stainless steel barrel. What do you think are the odds of rust in a screw hole being sufficient to cause such a failure?

---

This is why I don't think that there is much of an issue with the screw hole, yes it is weaker, yes there is a chance but the chamber area of the gun is never tapped, it is always ahead of this where the pressure is lower. Since the bullet is already moving by this point the pressure is not at its peak as it would be the instant before the bullet begins its trip down the barrel. This is why you see pressure graphs with spikes, the highest peak is at the point where the gasses have built up their maximum pressure before the bullet moves.

Stainless steel though can corrode, it does it all the time it just does not go as soft as iron oxide (rust) or as quickly. You can get pitting in stainless, you can get creep corrosion in stainless and you can get galvanic corrosion in stainless, the galvanic is the fastest and the worst. Galvanic corrosion is cool though, if you have 2 materials with very different internal charges one will corrode thereby keeping the other safe. Since this has to be in an electrolyte they use this technique for ships hulls and pipeline systems. Blocks of zinc are bolted to the ships hull, the zinc will corrode and protect the steel. They tried this in cars but air does not have enough electrolyte in it to protect the car and cars have tons of isolators in it so keep this idea from working too well.

Back to the original post, if you have the hole open you can get trapped water in there and start to rust the steel, this rust can work its way in and pit heavily which could cause a problem but I still highly doubt that would happen in a real world situation. Proof testing of barrels is required on all modern firearms, hence the "Proof Marks" on all firearms, in the early days you can link the age of a firearm to the stamp they used at the proof houses.
These proofs are significantly higher than the standard operating pressure of the firearm, this is why I cannot believe that a tapped hole (done properly and not too hot) could cause any failure irrelevant to if it were filled or not. That being said if you wanted to tap a thin walled barrel like a shotgun the gunsmith may advise against it due to the risk of going through the barrel. I have a 410 that I had sights put on for use with slugs and the gunsmith tapped the hole at the muzzle and dovetailed the rear because his machining practices lead to a greater control of depth on the dovetail and no risk of causing the metal in the barrel to press down into the barrel.

Quote:

---

Originally Posted by ET1

Having seen numerous pictures of barrel ruptures especially some with the 10ML-II one split of the barrel always seem to run through the rear screw hole. Coincidence, I don’t think so.


Attachment 28123


Ed

---

Still claim to not be insinuating that screw holes don't cause barrel failure? The entire premise of this thread is exactly this topic. For someone who likes to imply they are of a higher level on everything related to firearms, a guy who feels discussing the optimal pressure curves of expanding gasses on a forum like this, some here have questioned your advice and or motives. You are the one who drops the Engineer title and every third sentence it seems like. Anyway you are too predictable and obvious here. I'll leave you to your audience. But I can't help but repeat:
Where is the manufacturer of rifles and barrel data supporting your claim of these screw hole failures? Unless this is in your next response please don't bother, I know I'm done with this/you.

Quote:

---

Originally Posted by terrym

. I'll leave you to your audience.

---

Thanks that all we ask....LOL...

Quote:

---

Originally Posted by Fox

This is why I don't think that there is much of an issue with the screw hole, yes it is weaker, yes there is a chance but the chamber area of the gun is never tapped, it is always ahead of this where the pressure is lower. Since the bullet is already moving by this point the pressure is not at its peak as it would be the instant before the bullet begins its trip down the barrel. This is why you see pressure graphs with spikes, the highest peak is at the point where the gasses have built up their maximum pressure before the bullet moves.

---

Fox

I have a problem with your theory of pressure relationship to bullet moving.
Quickload program also says different as the bullet is moving before peak pressure is achieved.

Attachment 28129



Ed

Quote:

---

Originally Posted by ET1

Fox

I have a problem with your theory of pressure relationship to bullet moving.
Quickload program also says different as the bullet is moving before peak pressure is achieved.

Attachment 28129



Ed

---

I had read once that this was related to the pressure from the primer explosion, especially with the original shotgun 209 primers causing the bullet to move prior to full ignition. Now this was in relationship to BP as opposed to smokeless, so that may negate the comment.

No. Plugging the hole with a set screw will not add back reinforcement.
A round hole is not a sharp feature that will cause a sharp stress riser. This is why in RT, MT, PT, UT and even VT evaluation criteria rounded indications of certain size (dependent on which code) are allowable. Also why in structural members any (whether for lightening or for pass though of any other piece) holes must be round or have rounded corners.

A crack in a cylindrical pressure vessel (and that's really what a barrel is) will always propagate longitudinally as, practically speaking, "hoop stress" will always be higher than axial stress. Hoop stress is caused by the pressure acting radially from the center of the cylinder on the walls of the pipe/vessel in the circular x-section. Axial stress is caused by the pressure acting on the ends of the vessel (in the barrel this would be the breech plug and the projectile or barrel obstruction). I cannot explain why in barrels they seam to peel in 2, 3 or 4 places. In pressure vessel it is normally in 1 tear in the least reinforced, or most highly loaded axis (in a horizontal vessel the bottom of the vessel is slightly more highly loaded as it is under the the pressure but also under the head/weight of the whatever the vessel contains).

You can test this yourself. Fill a copper pipe (or even a cylindrical pop bottle) with water and cap both ends, throw it outside for a bit. Tell me which way it splits.

Certainly the hole, blind or not, within the barrel reduces the strength of the barrel. Plugging it with epoxy or a set screw isn't going to add integrity back into it, they are not molecularly bonded/fused. Plug welding would but then you are going to potentially warp the barrel, and damage the metallurgy in the area you are welding.

I would be more concerned if you are putting a screw in the threaded hole that it be stainless so as not to introduce any carbon contamination which can and will cause rust within the hole/threads that can propagate. Also putting a metal of different grade in that hole could cause additional stress as the barrel and plug would have different thermal expansion factors - albeit probably not enough for any serious or catastrophic effects.

MikePal

IMO I don’t think there would be much difference of bullet movement before peak pressure between smokeless and BP other than distance traveled by bullet. As seen by the video you graciously provided showing demonstration of different powder burn rates.
The 209 primer can also move bullet loads in the 10ML-II if powder doesn’t immediately ignite usually causing a misfire. Another reason I suspect this holds true is that the load in ml’s has no lands to overcome (restricting movement) as found in CF rifles.
So the theory goes anyway. :)



Ed

I would have to make a few assumptions on my part but I would believe that the pressure can be higher after the projectile begins to move. The projectile will move once the friction holding it in place has been overcome. The pressure causing this force may well be below the maximum pressure a given load of powder creates, and pressure may build faster than the volume (of the space behind the bullet) grows until the bullet gets some distance down the barrel, the bullet is moving ever faster and the powder charge is used up.

Just my opinion. I am not an Engineer, but I've dealt with some...and I think they stayed at a Holiday Inn.

Fishy Wishy

Tell you what read B31.3 of the ASME Code under Severe Cyclic Pressure Piping and tell me what it visually allows for surface porosity. I know that the procedure I'm required to use for dye checking has zero tolerance for even the smallest porosity for B31.3 Severe Cycling. Wonder why.

Any threaded area is considered having sharp stress risers and where accessible are usually checked with Dye or Mag inspection if NDT is required especially in-service components. You can argue that point with CSNDT who trains inspectors for CGSB certifications.
I know as I hold Level-2 RT-MPI-LPI along with Level-1 UT CGSB certifications.


Ed

Quote:

---

Originally Posted by Fishy Wishy

I would have to make a few assumptions on my part but I would believe that the pressure can be higher after the projectile begins to move. The projectile will move once the friction holding it in place has been overcome. The pressure causing this force may well be below the maximum pressure a given load of powder creates, and pressure may build faster than the volume (of the space behind the bullet) grows until the bullet gets some distance down the barrel, the bullet is moving ever faster and the powder charge is used up.

Just my opinion. I am not an Engineer, but I've dealt with some...and I think they stayed at a Holiday Inn.

---

Quickload agrees with your assumption.
And as seen the bullet is continuously accelerating while in the bore.

Ed

Quote:

---

Originally Posted by MikePal

I had read once that this was related to the pressure from the primer explosion, especially with the original shotgun 209 primers causing the bullet to move prior to full ignition. Now this was in relationship to BP as opposed to smokeless, so that may negate the comment.

---

Powder never fully ignites before the bullet leaves the gun, that is why you need faster burning powders with shorter barrels to maintain muzzle velocity.

The case containing the powder and closed with a bullet is a pressure vessel, it is as simple as that. The ignition of the powder makes an explosion of gases that pushes the bullet out the barrel. ET1 you mention that this pressure occurs after the bullet starts moving, I don't have a problem with that, what I have a problem with is that you make it seem as though the pressure is highest as the bullet is 6in down the barrel, which would have the pressure vessel now about 3 times the original volume, which would keep a lower pressure than at original ignition.

Once you drill a hole and tap it in the barrel you do make it weaker, but not by any amount that would cause a failure let alone with a screw in place or not. The screw in place is not molecularity part of the barrel and therefore has no impact on the strength of the barrel. If the barrel were layers that the screws were holding together then maybe, but a solid piece of steel with 2 tiny holes in it does not significantly change the strength of the barrel.

Fox

If the strongest part of barrel rupture doesn’t convince you what is probably happening then I don’t know what will.
But that aside I would more trust what Quickload reveals than an assumption on yours or anyone’s part.
IMO Fishy Wishy nicely described what happens when powder is ignited. The quickload graph basically supports his comments.

As for who is right about threaded holes take your pick as neither side can at this moment provide some more substantial proof to back their statement. That’s why I haven’t challenged it.
Believe whatever you want to presume and good luck.

One last thing, the whole bore can be considered a temporary pressure vessel and not just the brass casing, as pressure is not limited to the casing and also occupies the bore.

One other thing the smokeless powder does a progressive burn that is why there are powders classified with different burn rates.
When the powder ignites at the bottom end it pushes anything forward including unburned powder and the burn is usually completed outside the case.

Ed

Holy pissing matches! I will post some pics of how deep the rear sight hole is and it worried me actually. As for the steel screws in a stainless barrel, they come loctited in from the factory. There was definitely a gooey substance filling the hole when removed.

Back to the original post - there is no doubt in my mind that drilling a blind hole in a barrel will weaken it at that location. It's simple common sense. The barrel is thinner at the hole and it would make sense that it would fail there first. But my feeble brain agrees with what Terry and Fox have said, simply putting a screw in the hole does nothing to increase the integrity of the barrel. You would need to plug weld the hole and then hope that the heat from the weld didn't affect the temper of the steel.

Quote:

---

Originally Posted by M_P

Back to the original post - there is no doubt in my mind that drilling a blind hole in a barrel will weaken it at that location. It's simple common sense. The barrel is thinner at the hole and it would make sense that it would fail there first. But my feeble brain agrees with what Terry and Fox have said, simply putting a screw in the hole does nothing to increase the integrity of the barrel. You would need to plug weld the hole and then hope that the heat from the weld didn't affect the temper of the steel.

---

You would have to weld the barrel which would have to get the steel over the phase change temperature of the steel (depending on the carbon content this is around 1495C) then temper the steel to get the proper molecular structure back into the barrel.

https://www.google.ca/search?q=steel...ml%3B750%3B543

The fact is that the hole will make it weaker, but a screw will do nothing to make it stronger.

The reason sights are either mounted on the barrel or on the receiver is because the part that has to be the strongest and remain the strongest is the chamber area, this is why this area is so much larger that the barrel and tapers down (unless you have a bull barrel) to the barrel diameter to the length of the barrel.

The pressure is not highest 6in down the barrel it is at the chamber.

rippin - they would put thread locker in there to keep the screws in so that they did not fall out, the hot and cold cycles of a barrel are insane and those changes with dissimilar metals will cause loose fits in the threaded holes (think aluminum and copper wiring together). This threadlocker is also a barrier for moisture and therefore galvanic reaction as well, although the nickel and chromium content of most stainless does not have enough of a charge difference to react readily with steel. Holes in the barrel do not look nice, that is why most companies plug them, plus they hold water which will rust the non-stainless barrels.

Believe it or not, if your joints are too clean and your metals are too close to the same you can weld them together simply by putting them together, this is why you use 2 different classes of stainless for the parts and the fasteners when you install super clean stainless components.

I do this stuff for a living.

I don't know about this thread....

What is the point. If you blow the barrel it makes no difference whether a screw hole is filled or not.

That 10ml is proofed to 109,000 PSI. The fact that pressure went over that makes the point of filled screw holes kind of moot.

Quote:

---

Originally Posted by Big Jack

I don't know about this thread....

What is the point. If you blow the barrel it makes no difference whether a screw hole is filled or not.

That 10ml is proofed to 109,000 PSI. The fact that pressure went over that makes the point of filled screw holes kind of moot.

---

You've got that right!:thumbup:

Fox

Now I have a problem with your theory and only need to ask one question.

You are fixated on the powder being completely burned inside the casing and that max pressure starts there. If that were true then Boyles Law for pressure being inversely proportional to volumetric space would have the pressure 6” into the barrel greatly reduced. Yet we know if the bullet was stopped at 6” from the chamber the barrel would rupture.

So my question is where did this kind of pressure originate from that was sufficient enough to rupture the barrel that has a high tensile strength?

Ed

As stated before, installing the screw will not increase the structural integrity of the threaded hole in barrel. The hole should be plugged for corrosion prevention reasons.

The barrel is designed, tested and certified for its intended service life (usually unlimited) when operated within the design parameters specified by the manufacturer. Operating outside the so-called “design envelope” might result in failure, which will initiate at the “weakest link” of the barrel structure.

Boyle’s law relates to ideal gas transformations at constant temperature, very slow speeds, constant mass, and without energy transfer (within a “closed” system). Which makes it not applicable to the thermodynamic process that occurs inside the barrel.

Quote:

---

Originally Posted by ET1

Fishy Wishy

Tell you what read B31.3 of the ASME Code under Severe Cyclic Pressure Piping and tell me what it visually allows for surface porosity. I know that the procedure I'm required to use for dye checking has zero tolerance for even the smallest porosity for B31.3 Severe Cycling. Wonder why.

Any threaded area is considered having sharp stress risers and where accessible are usually checked with Dye or Mag inspection if NDT is required especially in-service components. You can argue that point with CSNDT who trains inspectors for CGSB certifications.
I know as I hold Level-2 RT-MPI-LPI along with Level-1 UT CGSB certifications.


Ed

---

I'm not experienced with B31.1 Severe Cyclic Loading. I am experienced with Sect I and VIII.

I currently hold none of those tickets...I did receive training and performed RT, MT, PT and had started UT training. I had finished my CEDO accreditation before I left NDE. I know a number of Level 3s in UT, RT, MT & PT in both GGSB and ASNT accreditations.

But this isn't a determination of NDE...this is understanding strength of materials and design.

The direction of the threads in the hole do not create a stress riser in the direction of the greatest stress.

A plug will not reinforce the barrel.

In a failure the barrel will fail in the weakest location...the hole definitely is going to create the weakest point so of course it will tear/splits there.

FW

Quote:

---

Originally Posted by Fishy Wishy

I'm not experienced with B31.1 Severe Cyclic Loading. I am experienced with Sect I and VIII.

I currently hold none of those tickets...I did receive training and performed RT, MT, PT and had started UT training. I had finished my CEDO accreditation before I left NDE. I know a number of Level 3s in UT, RT, MT & PT in both GGSB and ASNT accreditations.

But this isn't a determination of NDE...this is understanding strength of materials and design.

The direction of the threads in the hole do not create a stress riser in the direction of the greatest stress.

A plug will not reinforce the barrel.

In a failure the barrel will fail in the weakest location...the hole definitely is going to create the weakest point so of course it will tear/splits there.

FW

---

Fishy Wishy

There is no B31.1 Severe Cycling and Severe Cycling is only found in B31.3.
Section 1 is power boilers, Section 8 deals with pressure vessels and B31.1 deals with pressure piping. Because drawings are sometimes confusing showing the boundary of Section-1 and connecting pipe I hated to have to go back to the engineers for that boundary specification.

Everyone is entitled to express their thoughts and opinions on the barrel thread hole subject they feel is right.
I will say without more substantial proof from a reliable source neither one is proven correct or incorrect.

“The direction of the threads in the hole do not create a stress riser in the direction of the greatest stress.” According to who??



Ed

Quote:

---

Originally Posted by terrym

Still claim to not be insinuating that screw holes don't cause barrel failure? The entire premise of this thread is exactly this topic. For someone who likes to imply they are of a higher level on everything related to firearms, a guy who feels discussing the optimal pressure curves of expanding gasses on a forum like this, some here have questioned your advice and or motives. You are the one who drops the Engineer title and every third sentence it seems like. Anyway you are too predictable and obvious here. I'll leave you to your audience. But I can't help but repeat:
Where is the manufacturer of rifles and barrel data supporting your claim of these screw hole failures? Unless this is in your next response please don't bother, I know I'm done with this/you.

---

Someone who likes to imply things? Kinda sounds like you. You seem to be very abbrasive in replying to posts. Judging by the number of posts you have, you should get outside more!

Quote:

---

Originally Posted by rippin_355

Someone who likes to imply things? Kinda sounds like you. You seem to be very abbrasive in replying to posts. Judging by the number of posts you have, you should get outside more!

---

Now we are judging people by the number of posts they have on this forum ,that is bordering on the "ridiculous "

Quote:

---

Originally Posted by jaycee

Now we are judging people by the number of posts they have on this forum ,that is bordering on the "ridiculous "

---

Ridiculous is bashing people who are trying to be innovative and make things more efficient. If people want to play it safe and do the ordinary, then get a flintlock!

Quote:

---

Originally Posted by rippin_355

Ridiculous is bashing people who are trying to be innovative and make things more efficient. If people want to play it safe and do the ordinary, then get a flintlock!

---

Wow. Did you really say that? Pretty well proves my point again.

ET1,is correct. THe screws gives the integrity back and prevents rust especially the front holes. My brother is a retired gunsmith for the military.

Greenhorn

Thanks for providing and sharing that info from your brother who would be more knowledgeable in this area.


Ed