Another thread caused me to think about this.

Do small, independent barrel makers regularly proof test their products?
What about barrels that are furnished just as rifled blanks without chambers? If a gunsmith gets a .30 barrel, for example, would he know what cartridges it was rated to be chambered for?

If their markings are any indication, it seems that European regulations require all barrels to be proofed, but definitely not so much here.

(This is, BTW, a matter of curiosity, not concern. You don’t need to assure me that I don’t have anything to worry about. )

That's an interesting question.

I've only ever heard of ACTIONS being proofed. I have never seen or heard of a catastrophic BARREL failure, provided the barrel wasn't plugged up in some way.

I should think there are known formulas used to design a barrel contour where adequate material surrounds the chamber and the bore.

A good example of that is to do with some of the carbon fiber wrapped barrels that are now available. The bore itself is quite thin compared regular barrels. It also brings to mind the lightweight rifles that are so popular for hunters. Some of those barrels are very light and thin.

I don't really know what would be proofed, and against what standard. So let's see what other answers are posted here; I'm always happy to learn.

my (admittedly limited) understanding is that actions may or may not be proofed, ditto barrels,

however complete firearms are proofed,



re the barrels,

a barrel is marked on the end (of the blank) the twist, and bore diameter,


so a 30 cal barrel can be chambered in any 30 cal cartridge,

quote:

Originally posted by NikonUser:
I have never seen or heard of a catastrophic BARREL failure, provided the barrel wasn't plugged up in some way.

My understanding is that it happens sometimes with the really old shotgun barrels that were made by welding strips of metal together and which were intended for much less powerful shells than modern ones.

Most of the burst shotgun barrels like this are a result of plugged barrels, but anecdotally I've heard of it happening just from firing modern high-power shells through really old shotguns.

Either way, old shotgun barrels aren't really relevant to this discussion, so effectively, I agree with you.

The increased quality of materials and more refined manufacturing techniques used today make proofing a lot less important than it used to be.

300 years ago, when you had a brand new cast cannon that might have a big air bubble hidden beneath the surface, you wanted to be damned sure it wasn't going to blow up on you.

Yeah, those are Damascus steel barrels. I seriously doubt independent barrel makers produce those anymore.

The USA does not have proof law and proof houses like European countries. But liability conscious manufacturers still proof test completed guns. There is SAAMI protocol for it.

Hard to proof test a barrel blank and I have not heard of proof testing unassembled actions.

I have heard of gunsmiths proof testing custom or modified guns but not very often. They - and you - are depending on the quality of the parts they use.

I didn’t think about the fact that it’s rifle actions that are proofed, not only the barrels. On the other hand, autoloading pistol barrels get marked with proof marks in Europe, and that was in the back of my mind.

About barrel blanks, I was wondering if someone wanted to chamber one for the 7.82 Warbird that seems to be one of the largest .30 loadings, would any .30 caliber barrel do, or would the blank maker specify chamber pressure or cartridge size limits?

Thanks for the comments.

quote:

Originally posted by sigfreund:
I didn’t think about the fact that it’s rifle actions that are proofed, not only the barrels. On the other hand, autoloading pistol barrels get marked with proof marks in Europe, and that was in the back of my mind.

About barrel blanks, I was wondering if someone wanted to chamber one for the 7.82 Warbird that seems to be one of the largest .30 loadings, would any .30 caliber barrel do, or would the blank maker specify chamber pressure or cartridge size limits?

I would think the primary limiting factor would be the action itself, since the barrel diameter/threads/sizing will be dictated by the action size and whether it can handle the Warbird or any other similar cartridge. Then you can get into the discussion of of the chamber portion of the barrel outside of the action.

quote:

Originally posted by BGULL:
I would think the primary limiting factor would be the action itself ....

Ah; good point.

Did I already say this was an interesting question?

I went over to Kelbly to look at their actions. They post the exact sizes of their actions along with dimensional drawings.

What I noticed is that for all their actions they have the exact same diameter for the threaded barrel: 1.0625 or 1 1/16 inch. The thread is 18TPI.

So the exact same diameter for actions that can handle anything from .223 to Magnum calibers, the determining factors are boltface diameter and length of the action. The boltfaces they list are 223 (.378), 308 (.473) and Magnum (.532).

They have actions for .338LM, but no dimensional drawings. The boltface for the 338LM is .587. I think. The one for the 50BMG is over .830. So I'm guessing these two, along with things like the 416 and so on may have bigger barrel shank diameters.

For what it's worth, remember that SAAMI is a Society, not a government-owned organisation. It has no powers, per se, just best-practice recommendations.

Here in Europe, in a total of fourteen countrties currently, gun proof is part of the historical record, established in some cases in the late 1500's. The UK has had compulsory but self-instituted proof laws since the early 1800's, with Proof Houses being run and organised by the gunmakers' guilds. The same in Germany and Italy, whose historical gunmaking goes back to the very beginning. Beretta is the oldest-established family-owned gunmaking company in the world, BTW . In recent years the CIP organisation has been instituted to rationalise the SAFE manufacture of small arms and ammunition, and has, right now, fourteen members who have taken the recommendations into the Law of the Land. Here in UK there are now just two Proof houses - London and Birmingham, still the homes of 99% of English gunmaking. The Dublin Proof House was closed down over a hundred years ago...

This means that EVERY single US-made small arm coming to the CIP nations to be sold - and trust me, the US share of sales is simply VAST - has to be proofed in accordance with the documented standards. Revolvers have to have each chamber proofed. There are no exceptions to this - it is the law.

I'd like to say that I've never heard of ANY US-made small arm failing proof.

This message has been edited. Last edited by: tacfoley,

quote:

Originally posted by tacfoley:
This means that EVERY single US-made small arm coming to the CIP nations to be sold - and trust me, the US share of sales is simply VAST - has to be proofed in accordance with the documented standards.

Thanks for that discussion, tac.

An example of an S&W revolver with German proof marks.

quote:

Originally posted by sigfreund:

About barrel blanks, I was wondering if someone wanted to chamber one for the 7.82 Warbird that seems to be one of the largest .30 loadings, would any .30 caliber barrel do, or would the blank maker specify chamber pressure or cartridge size limits?

Quick look at the chamber pressure of the 7.82 Warbird... no big deal. Calibers such as a the 6x47 are loaded at similar or higher pressure.

quote:

Do small, independent barrel makers regularly proof test their products?

No. Know need to, If they use USA made and certified barstock in the correct steel and stainless steel alloys.

quote:

What about barrels that are furnished just as rifled blanks without chambers? If a gunsmith gets a .30 barrel, for example, would he know what cartridges it was rated to be chambered for?

The weak link is generally not the barrel steel these days, it is the brass alloy cartridge case. The exception to this may be some stainless steel alloys such as 416R may not be the best choice for light contour stainless barrel in very cold weather... at least on paper. Sako did have a problem with this back around 2005 give or take and recalled some SS ultra light style magnum rifles that did blow up in cold weather. The Pics I seen at the time showed the barrels split inside the thin flutes area. And get this... those rifles had European proof test marks on them.

As far as I know SAAMI does not allow any cartridge to operate above a 65,000 PSI ceiling. That is about the limit of a very good brass alloy case. Although the 6mm PPC Benchrest type rifles run around 68,000 PSI. But that another story.

quote:

Originally posted by Jelly:As far as I know SAAMI does not allow any cartridge to operate above a 65,000 PSI ceiling. That is about the limit of a very good brass alloy case. Although the 6mm PPC Benchrest type rifles run around 68,000 PSI. But that another story.

However, SAAMI is not a regulatory body, but a branch of the American National Standards Institute with no powers in law. The CIP regulations are exactly that - part of the law of the nations that have signed up to them. CIP also covers all small-arms ammunition.

quote:

Originally posted by Jelly:
(snip)
The weak link is generally not the barrel steel these days, it is the brass alloy cartridge case. (snip)

I'm going to take some exception to this comment.

The brass case is really only used to keep the components together outside of the rifle's chamber and to make it easy to load and fire. The brass case is NOT designed to contain the pressure generated by the sudden transformation of the solid powder into a hot gas. That's the function of the chamber of the barrel of the firearm. Under firing conditions, the brass case expands to the walls of the chamber and obturates it so as to prevent any leakage and thus concentrate the entire expansion of the gases out the bore, pushing the bullut in front of it.

If it were not for the chamber walls, the case would immediately rupture or the bullet would pop off at the first hint of pressure and the whole thing becomes a big dud as the propellant used in ammunition requires pressure to really do its thing, burn really fast and generate 1000 times its volume in gas.

Brass has several properties that make it very useful in firearms:

It is ductile, which means that it can deform under tensile strength.
It also malleable which means it has the ability to distort when pressure is applied to it.

When you put these two properties together, you have something know as plasticity; this means that it the brass case can be deformed before it breaks or fracture. You can think of glass as something that does not have plasticity.

However, plasticity is not the same thing as another property known as elasticity. Plasticity is permanent, elasticity is temporary; the brass can be deformed but it does spring back. Brass will be elastic until it becomes plastic.

When you fire a cartridge, the brass case is subjected to pressure. Its ability to deform (plasticity) is what gives us the obturation that we want of the case; close up all the gaps and direct the expanding gases out of the bore to push the bullet.

The walls of the chamber prevent the brass case from expanding too much, past its fracture point. When the pressure is removed the elasticity of the brass will cause the brass to return to its "original" shape, contracting the case and moving away from the walls of the chamber and ending the obturation process. You are then able to open the bolt and remove the fired case.

Brass has a point where when subjected to pressure, the elasticity is lost and the plasticity rules. Pretty much anywhere above 45,000PSI, the elasticity of the brass starts to lessen until you get to about 68,000PSI, at which point, the elasticity is gone and the plasticity of the brass makes that shape permanent.

After firing, the brass is supposed to contract a little bit and this allows the bolt to cycle and the fired case can be removed. However when the pressure is too high, the brass does not contract enough to allow smooth bolt operation and the bolt handle becomes difficult to lift; that's when you know that you are already in high pressure territory. The bolt rotates the case to effectively break the seal with the chamber wall and the case can be extracted. If the bolt can't rotate because the brass did not contract, the case is not coming out.

Yes, the bolt and the chamber of a rifle have higher tolerances to pressure than the brass case. That's why I see people on the line opening their bolts with hammers, as a matter of course. Everybody thinks their rifle can handle their hot loads. The problem is the effects are cumulative and subjecting the bolt to continuous overpressure will wear out the lugs and do other things. It's also very hard on the brass itself. I know of competitors who load to insane pressures and throw the brass away after the first firing; with its elasticity all but gone, you can't resize that brass.

We resize the brass because even under normal pressures it does not snap back all the way to its original dimensions; it needs a little help. Annealing does restore the elasticity of the brass, but you can't anneal the entire case, only the neck and shoulders. The lost of elasticity at the case head is what prevents it from being used again.

Just as a note, case head separation, even with normal pressures, is an example of why the brass case is not able, by itself, to contain the pressures generated by the combustion of the propellant. Case head separation is caused by headspace issues where the shoulders of the case are not firmly in contact with the chamber walls and the body of the case has room to grow past its fracture point. When the case head ruptures, the obturation of the chamber is compromised and gases leak at that point. The net effect is a low shot on target and crap all around you. I can tell you a funny story about that.

ETA: Typos fixed.

This message has been edited. Last edited by: NikonUser,

Thanks, NikonUser, for your good description of all that. I was aware of everything you discussed, but could not have explained it so well.

^ The cartridge case is just a gasket.

NikonUser - an exceptional description. Well done.

Should you ever get to town that deserves a free beer!

When I made my .45 caliber flintlock rifle, I proof tested it. And I proofed my Brown Bess when I got it, but never tested any AR 15 barrels....I assumed they were test fired at the factory. I’ve never had a barrel blank turned for a bolt gun.

I will be replacing a Rem700 in 243 in the future and I wonder if the new REMAGE barrels are tested.