what does it mean to "ring" your barrel

[wyobohunter]

I have heard of this, I'm sure it is damaging in some way, I just don't know the cause/s or effect/s. Thanks.

[b.thomas]

Only barrel "ringing' I know of is with sxs shotgun barrels?
Basically a method of testing the solder joints between the barrels;
Clear ring means your solder is solid and a one with a bit of a "buzz" means something loose.

[Sevens]

When you stick a bullet in your barrel, it sits there, stuck.

If you shoot another behind it, the two bullets don't actually touch-- the column of air between them goes quickly from an inch or 2 or 3 to none, and that column of air gets compacted and when the two bullets are as close at the compacted air will let them get, the barrel gets "ringed" or bulged. Both bullets typically fly out of the barrel.

After this happens, you can often shoot as normal with a revolver, but most semi-auto pistols will not function as the barrel won't move in the slide.

Accuracy is usually destroyed, but I've heard plenty of cases where it still manages to shoot well even with a ringed barrel. With a revolver, you can usually run your hand down the outside of the barrel and feel the bulge.

[Scorch]

Ringing the barrel refers to a ring bulge. There are several ways to get a ring bulge in your barrel, one of which is trying to shoot out an obstruction in the bore. Another is firing the rifle with water or oil in the bore. The bullet eventually rides up over the liquid and forces it outward. Since liquids do not compress very well, it forces the barrel metal to expand at that point.

[James K]

The response about barrel bulging is correct, but not the reason for the bulge.

When a bullet (or any not easily movable object, like an oversize patch) is stuck in the barrel, and a second bullet is fired, the second bullet will build up kinetic energy as it moves. When it stops suddenly at the obstruction, that kinetic energy is instantly changed to heat, which is enough to actually soften the barrel so it will expand from the pressure of the gas behind the second bullet.

It is not the air trapped between the bullets that bulges the barrel. The same thing happens if you drill a hole in the obstruction to allow the air to escape.

That is also why it is possible to shoot out an obstruction without bulging the barrel using a moderate powder load but NO bullet in the second cartridge. There is enough pressure to move the obstruction, but the gas alone does not have enough kinetic energy to convert to heat and soften the barrel.

Jim

[Unclenick]

Jim,

I think I can prove to you that the thermal conductivity of steel is far too low for heat to spread from the bore surface into the barrel steel in the time it takes for the bulge to form. It would be red hot at the bulge if it did. Indeed, you've probably noticed that after firing a shot, the barrel surface doesn't start to reflect the added heat for several seconds. Instead what will happen is the new bullet will crash into the stationary bullet and try to share its momentum with it (an inelastic collision rather than an elastic one, such as billiard balls, where a straight strike can transfer all the momentum to the second ball). That is like accelerating the second bullet to half velocity in just a quarter of an inch or so. The required force is immense and distorts the two bullets at their interface, translating energy laterally (obturating them) to form a bulging ring of bullet metal and transferring that lateral bullet bulge to the barrel steel, which is propelled outward at its mean center. When the barrel exceeds its elastic limit the energy that does not spring back out is translated to heat, which is why a bulge feels hot immediately after forming and not seconds later. The heat you noted, in other words, is a symptom of the bulge mechanics and not its cause.

As to the bulged bullet material, it proceeds forward to be swaged back to diameter by the remaining barrel.

Nick

[Harry Bonar]

Sir;
Put your wedding band on the barrel - let your wife see it and your head will ring!
Harry B.

[Dfariswheel]

Another great way to ring or bulge a barrel is by "shooting the lead out" by firing jacketed bullets after shooting lead bullets.

The jacketed bullet has to push the lead in front of it like the bow wave of water in front of a boat.
Too much lead, and it can't move out of the way fast enough. Something has to give and the barrel rings or bulges.

[darkgael]

A question related to the original and to several responses. I'm not being a wise guy, I really don't know.
" That is also why it is possible to shoot out an obstruction without bulging the barrel using a moderate powder load but NO bullet in the second cartridge. There is enough pressure to move the obstruction, but the gas alone does not have enough kinetic energy to convert to heat and soften the barrel."
"the new bullet will crash into the stationary bullet and try to share its momentum with it (an inelastic collision rather than an elastic one...."
When loading CF rifle cartridges with reduced loads, we are frequently warned NOT to use fillers in bottlenecked cases because that practice has been known to cause ringing of the barrel just after the chamber or even in the chamber. We have a light powder charge and a very light wad or filler. What causes the ringing in that case? Or....is that caution another myth?
Pete

[James K]

Hi, Unclenick,

Sorry, but it is the heat that does it, not bullet expansion from the pressure. The heat comes and goes very fast (not even fast enough to discolor the bluing) but it is there.

Have you ever fired a bullet at a steel plate (yes, I know you shouldn't) and observed the way the steel splashes. It looks exactly like those high speed pictures of a drop of water hitting the surface of water. Same crater, same "crown" appearance, same drops spashing up. For one instant, that steel and that bullet were so hot that both the bullet and the steel plate actually melted and splashed up when the bullet's kinetic energy was changed into heat. The only difference between the steel and the water is that the steel absorbed the heat quickly and "froze" while the water just flowed back into the crater.

That is also how armor piercing bullets work. The bullet strikes the steel and the heat causes it to become, for an instant, like a soft putty that the hardened carbide core then penetrates. If the steel is too thick, it will absorb the heat causing the surface to solidify before the core can penetrate more than a few millimeters. The result is seen in tank armor where a machinegunner has fired AP bullets at the tank and they are stuck in the armor.

HTH

Jim

[brickeyee]

Even if you converted all the energy in the bullet instantly to heat it would not raise the temperature of the steel enough to do anything.

1 ft-lbf is 0.3238 calories.
Even if you had 2000 ft-lbf, you only have ~656.6 calories of heat.

[James K]

So what causes those steel spatter marks and drops on a steel plate. And what causes .22 bullets to spray molten lead all over when they strike a rock? That steel and that lead were LIQUID, folks, for that instant. I suggest a talk with a physics professor and maybe some experimentation with instant recording heat gauges.

Jim

[fourdogs]

I'm no physicist, but I think it's the combination of heat produced by pressure, and the pressure itself ( shock wave ) It's true as far as I know, that an anti tank round will burn a very small hole through the plate, and then bounce hot fragments around hoping to explode something inside. Remember that when a round travels down the bore, the barrel actually bulges, but that's very different than ringing your barrel.

[Harry Bonar]

Sirs;
At a certain amount of pressure brass becomes like plastic, steel becomes plastic to the point even that lead (softer than steel) will "penetrate" steel! Now, it seems to me that it is a measure of molecular motion and I guess you would call that "heat."
How can soft lead penetrate hardened steel? Heat - molecular change brought about by a facility/friction/heat!
How fast does it happen? -nanaseconds!

Steel, or any other molecular substance under heat will deform - jet aluminum aircraft allow, 4140 steel - some people calll it metal fatigue - it can happen fast with a bullet ringing a barrel or slow with a jey losing a wing!
I never thought about "heat" ringing a barrel till Jim clarified it, but thinking it through he is technically correct (as usual - darn it).
Harry B.

[James K]

Just to clarify, I was referring to the classical "armor piercing" rifle bullet, like the .30 AP "black tip" with a carbide core. Modern anti-tank rounds typically use shaped charges that blow a super hot gas jet through the armor, a whole different concept and of course not at all practical in a normal rifle cartridge.

During WWII, AP rifle ammunition was commonly issued to U.S. troops because it did penetrate light armor (like some gun shields) and heavy truck bodies; it could not, and did not, pentrate tank armor, even the lightest. At Aberdeen, there is (or was) a German tank whose turret had a dozen or more AP cores sticking in it. That was the result of the AP bullet impact melting the steel enough to let the core penetrate a short distance before the heat was dissipated in the heavy armor and the molten metal "froze" around the core.

Of course with thin metal (say a tin can), there is far too little resistance to a bullet for any significant energy transformation; the bullet penetrates by pure force.

Jim

[brickeyee]

Modern anti-tank rounds typically use shaped charges that blow a super hot gas jet through the armor, a whole different concept and of course not at all practical in a normal rifle cartridge.

While there are still HEAT rounds (High Energy Anti Tank), the 'state of the art' is a 8 pound depleted uranium (DU) dart.
The main body is a little over an inch in diameter.
At the striking velocity the DU is heated enough to start burning, and the the impact is on such a small area that many inches of armor can be penetrated followed by the spray of both the armor and the burning DU.

Being plastic under impact does not imply that the material has actually melted to a liquid.
Strike some wood with a hammer.
The wood did not melt, but was still plastically deformed.

The same thing happens with lead bullets since lead is both soft and malleable.
Smack a bullet with a hammer. It did not 'melt' but has been deformed.
Note that a 2 pound drilling hammer has a huge amount of energy.

The hardened core of AP small arms bullets allows the energy of the impact to be concentrated in a smaller diameter than the overall bullet, increasing the force generated on the target.

[FL-Flinter]

Ringed/bulged bores are caused by the pressure and not the bullet/shot charge/ball. A rifle barrel fired with an obstruction such as a stuck bullet, slug of snow, mud wasp nest, dirt or whatever will often not be damaged where the actual obstruction is, the damage will be at some point prior to the obstruction. Look at this picture and you'll clearly see where the barrel bulged prior to where the actual obstruction was, the bulge took place first and when the barrel reached its maximum elastic point then it started splitting.


Anything that causes the projectile to slow down will cause the pressure behind it to raise considerably and very rapidly. It has nothing to do with heat because the barrel steel cannot absorb enough heat fast enough to have any effect on the failure area. This is why a shotgun barrel plugged at the muzzle will often shed a portion of the muzzle end - the pressure spike causes the thinnest portion of the barrel to fail first many times resulting in the portion being torn away and the remaining section flared and/or split.

The end result of any failure is directly proportional to all the factors involved. Certain powders used under certain conditions can also cause a barrel failure giving the appearance that a bore obstruction was involved even though it was not - this is commonly referenced as "SPS" or Secondary Pressure Spike that is caused by the nature of the powder burn itself. During an SPS event, the bullet itself becomes the obstruction simply because it cannot increase its velocity to match that of the pressure rate of rise behind it.

I often hear comments being made about barrels having symmetrical splits from a failure - first thing is, most rifle barrels do not have rifling grooves that are deep enough to cause a "zipper" effect but deep exterior profile flutes/cuts can have somewhat of an effect on the direction of the failure but it all depends on where and how the failure is initiated. If you look at the picture above, that is about the best you can ask for in a catastrophic failure - the barrel peeled back somewhat symmetrically and it doesn't appear that any large chunks were lost. A barrel that peels rather than fragmenting is a blessing because it usually allows the pressure to vent off in directions out and away from the shooter - if something is going to turn loose, that's about the best outcome you can ask for.

Back to shotguns, look back to the 1990's when some people tried shoving big steel shot pellets through bores with full or tighter chokes. The classic failure didn't start at the choke but rather some distance prior to the choked section and when the failure was properly reconstructed, the point of origin was at or near the powder-end of the wad column where the pressure from the powder burn exceeded the strength of the barrel. In some cases a failure will be nothing more than a small bulge and split that allowed enough pressure to vent without a complete catastrophic failure occurring. In other cases, the shotgun barrel opened up much in the same manner as the rifle pictured above. I bought a 12ga Steven singe barrel, the 30" bore was plugged with mud when the previous owner fired a 1.125oz load of #8 lead shot (Winchester AA trap load if you're curious) the last 10" or so on the muzzle end opened up like a flower, perfect symmetrical pattern with the bulge section as seen above.

BTW - you can swell or ring a barrel without it breaking - that is the most common definition of "ringing" be it in the bore or chamber.

[James K]

Hi, Brickeyee,

No, the AP core does not just penetrate because the energy is concentrated, it penetrates mainly because the steel it is being forced into has been softened by the heat generated by the bullet envelope striking the steel and giving up its kinetic energy.

Hi, FL-Flinter, unless the barrel was defective to begin with, that barrel split because of the obstruction and the split began AT the obstruction. When the pressure began pushing on the sides of the barrel, it bent the pieces out in the typical "flower bloom" shape, with the breakage along the rifling cuts. In some cases, the split barrel will continue back far enough to split the receiver ring. In a widely reported case with an M1A, the barrel split in two halves, top and bottom (due most likely to an inclusion flaw), and the receiver ring was broken. There had been no barrel obstruction. The fired case remained in the chamber and did not even show signs of high pressure; the top of the barrel simply peeled away from it.

Jim

[FL-Flinter]

Sorry Jim, I'm going to disagree with you based on the numerous ruptured barrels I've seen with my own eyes. Mud & snow were the most common causes of ruptures but one in particular was a dime. Someone dropped a dime down the bore of a 12ga Remington 870, probably to check the choke but that someone failed to remove it and the fellow who fired it failed to check the bore prior to loading it. The dime was stuck sideways in the choke as was indicated by the opposing metal transfer lines that were exactly 180° opposite of each other. The bulge in the barrel started about 1.750" before where the metal transfer marks located - that distance is roughly equal to the length of the shot and wad column plus half the diameter of the dime itself clearly indicating the failure started at the base of the wad column and not at the obstruction itself.

Mud wasp nest in a .308win rifle bore. Bulge started a little over an inch prior to where the rust pits indicated where the mud started thus the failure was initiated at the base of the bullet and not at the point where the bullet met the obstruction. The same conditions were seen on a .270win bore that was also fired with a mud wasp nest in it - in total probably half a dozen victims of mud wasps, everyone showing the failure initiation point at the base of the bullet, no the nose.

20ga Ithaca/SKB recoil-auto fired with $600 in cash stuck in the muzzle (husband saving up for a new rifle was hiding the money from his wife. Two $100 bills the rest in $50's rolled tight together and stuck in from the muzzle. Barrel bulged 1.5" behind where the money roll was - again clearly showing the failure initiated at the end of the wad column and not where the shot column came in contact with the obstruction.

Muzzleloader operated by some yahoo that thought loading two balls would be better for hunting. Likely would not have done much more than wreck accuracy if he had fully seated both balls be he left the second one hang at the end of the short starter. Barrel bulged and opened a narrow split but did not open-up completely like a flower. Laying the short starter alongside the bore then adding two balls matched up perfectly with the widest point of the bulge or at the base of the ball, not where the two balls met.


If you're talking about the M1A that splintered into numerous pieces (green or camo if I recall) that was not from an obstruction, it was incorrect powder - rounds loaded overseas charged with powder intended for .30carbine if we're thinking of the same incident. Detonation/overpressure is not in the same category as an obstruction - same thing with failures attributed to design/manufacturing flaws - apples and bowling balls, completely different.

Mark

[smiljko]

I have a quick question-is it safe to put electric tape or finger from latex glove over the muzzle to prevent snow and mud entering, and of course to shoot through it. I'm talking about .30-06 rifle.
Thanks

[James K]

Hi, smiljko,

Using tape, a latex glove finger or some other tubular piece of latex (unmentionable) over the end of the barrel would be no problem at all and it can be shot through. In fact, I recommend it and there have been muzzle caps sold for that purpose. Just don't put any plug INTO the barrel.

Hi, FL-Flinter

As to barrels bursting, I didn't say where the burst is in relation to the moving bullet, nor did I say that pressure plays no role.

A long time myth was that the barrel burst because of the air pressure between the bullet and the obstruction. Then experimenters drilled a hole in the obstruction, and the barrel still burst. Also, many folks noted, as you have, that the burst was not between the bullet and obstruction, but behind the bullet.

For simplicity, let's say the obstruction is a bullet, B1, in the barrel of a rifle. A second bullet, B2 is fired down the barrel. The scenario is as follows: B2 builds up kinetic energy as it moves. The further it moves, the more energy it builds. Suddenly it is stopped by B1. The law of conservation of energy says energy can neither be created or destroyed, only changed into another form of energy. So the kinetic energy built up in the bullet has to go somewhere, somehow.

The only thing that can happen is that the energy is transformed into heat. That heat is enough to soften the barrel steel. The pressure behind B2 then will push the barrel wall outward at that point, with the results you noticed.

The result is usually a bulge or, more rarely, a bulge and a crack. But when the barrel bursts near the muzzle, it will usually do as shown in your picture. Fluted barrels will, naturally, split along the fluting, that being the weakest part of the barrel. The split will not necessarily be only behind the burst point. Once the split begins, it can go both ways, splitting the barrel toward the muzzle as well as toward the breech. Remember, tremendous pressure is pushing on those strips of steel, so it is like pry bars trying to pull them apart. In the M1A case, the barrel strips themselves became pry bars, tearing the receiver ring apart.

That rifle in that M1A case I mentioned was analyzed by metallurgists and the conclusion was that there was a flaw in the barrel, not overpressure from a defective cartridge. As I said, the empty case was lying neatly in the bottom half of the chamber, showing no signs of high pressure or bursting. The barrel did not burst due to high pressure within the case, the barrel split starting at the front and peeling away from the case like a banana peel away from the banana. By the time the split got to the chamber, there was no more internal pressure in the case and it simply sat there.

Jim

[Unclenick]

The melting explanation is not possible for several reasons. One is the lower melting point of the copper jacket and the much lower melting point of the lead core would cause them to melt first, absorbing energy by enthalpy of the change of phase, acting, in effect, like ice cubes relative to the melting point of steel. Instead, you find broken jacket pieces on steel plates, clearly not melted to a splatter. Lead splatter does occur because of its extreme malleability, but I haven't seen it appear melted.

The other problem is that while there exist some ways to heat metal very fast, such as an induction furnace that heats it simultaneously inside and out, or stretching or deformation of the metal volume which produces internal stretching friction, there is no way to get heat out of steel in a flash. Nor is there any way to get it into the steel in a flash when it is applied at the surface. Both cooling and heating from the surface are limited in transient velocity by the simple specific heat and thermal conductivity of the steel. Period. A good example of that limitation in action is when a rifle throat develops heat stress cracks, which constitute the alligator skin pattern that appears when enough rounds have been fired through it. That pattern occurs because the heat of the burning powder and combustion gases only penetrate a very short distance into the surface while the bullet is in the barrel, expanding only the heated metal at the surface. The base underneath hasn’t had time to warm equally and the expansion differential between it and the hot surface produces the cracks. If the heat could enter the steel in a flash, that would not occur.

It seems to me we might want to distinguish a couple of different barrel bulging phenomena. People often fail to consider that propellant gas has mass and forward momentum. That gas is what produces rocket effect at the muzzle which can be responsible for 40% or so of total recoil in some high power overbore rifle loads. Relieving that pressure laterally before a bullet exits is why muzzle brakes reduce recoil even if they are jetting the gas in all directions simultaneously, and not just in opposition to recoil or muzzle flip. If a bullet is being chased by the mass of an expanding high pressure gas column and stops suddenly, the gas’s momentum piles it up forward and compresses it to much higher pressure. That creates a barrel bulge just aft of the stoppage. This is usually a very visible bulge and is typically spread over two or more barrel diameters, all the way up to, and including barrel bursting. I believe this is the phenomenon FL-Flinter is referring to as it explains the location of the bulges he describes.

The other phenomenon, which is the one I call ringing, is much more localized. It resembles ringing of a chamber by shooting overly warm cereal filler loads. It often is only a quarter of an inch or so in length, and its bulge is typically much shorter and less pronounced than you see in a gas pressure bulge. In a thick barrel you may not see the bulge at all with the naked eye. It is this ring that I believe to be an artifact of the bullet collision interface.

I’ve been PM’ing a bit with one of our European members who described four Anschutz .22 LR club gun barrels apparently suffering from the latter phenomenon. He could feel a cleaning patch slip past the ring, but could observe no bulge at all in the barrel exteriors. He had no micrometer with which to measure the barrel OD’s at the time. A micrometer would be expected to reveal at least a small surface upset. .22 LR barrels are usually fairly soft as barrel steel goes, but even so, the cartridge involved does not have the energy nor does it generate the volume of gas typically expected to produce a pressure bulge. Especially not very far down the barrel. It is, I still think, bullet collision collapsing the nose of the rear bullet laterally outward that produces a localized ring with small or no obvious external bulge. I am prepared to be proved wrong if it can be demonstrated that gas pressure can be localized to produce short rings. Interestingly, these small rings produced no observable accuracy deterioration.

You occasionally see one of those pictures of a sectioned revolver barrel that has four, five or six bullets piled up in it. It would be interesting to apply a micrometer to identify bulge centers in one of those.

[darkgael]

UnClenick: "...... ringing of a chamber by shooting overly warm cereal filler loads"

If you have a moment, I'd like more info about that phenomena. I posted the question earlier but it has remained unanswered. I have not ever found a consistent explanation of the mechanisms involved in the "cereal filler/ no wads in bottlenecked cartridges idea". It's something that I'd like to know.
Hope you can help.
Pete

[fourdogs]

This is an excellent thread. Thanks to all. My overly simplistic view about piercing metal ( not shaped charges ) was the shock wave pulse played a major role in deforming the metal, especially if the projectile approaches hyper velocities.

I was always impressed when my 220 Swift with a little 60gr hollow point would punch clean through a 5/16" steel plate at 50 yards. The holes made a crater with metal flowing forward around the rim, as well as flowing backward.

[James K]

Hi, fourdogs,

Well, maybe the other folks would like to explain how that steel flowed backward from the bullet strike since they say there was no heat involved. And where those molten lead drops come from when a .22 bullet strikes a rock since they say there is no heat involved. Actually, you get an even more impressive "splash" when the bullet doesn't penetrate, so all its energy is converted to that heat that doesn't exist. Try a 1/2" or 3/4" cold rolled steel plate instead of a 5/16".

Come on folks, physics explains it all.

So let's shift the topic a bit. I ran an experiment using an old .45 pistol barrel. I drove it full of lead bullets from the breech until there was just enough room to insert a GI ball round. I then put the barrel in a pistol and fired it into a sand trap. What do you guys think happened?

Answer: Seven bullets in the sand trap.

Jim