Rung Chamber

[Boz330]

We have all been told that that you have to be careful about airspace in BP rounds and I have heard some people say that a little won't hurt anything. If you look at the picture of the case that is attached, there are 2 different places that indicate a rung chamber. The first is kind of a blister looking place at an angle and then another is above that perpendicular to the case. Neither area goes all the way around the case and isn't deep enough to cause extraction problems, but this happened to a brand new barrel and with that it is rather disconcerting to say the least.
At first I thought that maybe there was a flaw in the barrel metal that showed up after I had shot it some. I called Badger and talked to Ernie Stahlman who was very patient with me in his explanation of what might have caused this. I am going to try and explain this as close as I can remember his explanation.
The first one showed up while I was trying to develope a load. I was just thumb seating the boolit on top of 58gr of 2F Swiss and was trying out different weight boolits. Ernie asked if some of the boolits were pushing back out of the case from trapped air, and I said that some of them did but the boolit was seated fine when I chambered the rounds and closed the block. His contention was that the trapped air from the lubed boolit didn't exit the case and was still in there. Second question he asked was did I have any rounds that were way out of the group vertically that couldn't be explained by operator error. Again the answer was yes. His explanation was that in an ideal world the BP should burn from the back of the case to the front similar to a solid fuel rocket, but sometimes the fire will go to the side of the case were the powder may not be compressed enough and burn up the side of the case in looser powder and then burn back towards the center, or towards the flame coming up from the bottom. When this happens the preasure really spikes causing the high boolit strike. Now combine this with the air that was trapped in the case and you have the combination for a rung chamber.
Now when I say the round was out of the group vertically, I'm talking 18 to 24 inches above a 2 to 3 minute group of 10 rounds. I always check groups at 300yd for load developement. His suggestion was to MAKE sure that all of the air was out of the case by twisting the boolit and making sure the boolit stayed down against the wad, and using compression on the powder to make sure there wasn't a loose place in the powder column where the fire could burn forward and ignite the front of the column.
I have since gone to neck tension which gives me better groups anyway and did in the previous barrel.
I don't pretend to understand everything that goes on inside a case during ignition but thought that I would throw this out for rumination.

Bob

[Pepe Ray]

Since you've already spoken with the expert, I'm sure you've got a handle on it.
However ,If it were me, I'd have blamed it on a flawed case. Until every case came out the same.
Very interesting post, Thanks.
Pepe Ray

[Boz330]

Every case is and you could feel the flaws with a dental pick in the chamber.

Bob

[August]

Boz:

Thanks for this very sobering report. Damn, that hurts on a new Badger barrel!!!!! I guess the cost of putting together a compression die isn't so important after all. Thirty bucks for a die sure beats 600 bucks for a barrel.

I appreciate your excellent explanation. I've always known of this hazard, but understand the process better now.

This is also the reason why I don't like to use filler in smokeless loads. Suitable powder and attention to loading density are serious issues in them big ol' cartridges.

[martinibelgian]

Bob,

I'm one of the guys shooting with air in the case, and after close to 1000 rounds downbarrel in - among others - an antique, soft-steel 577-450, no issues yet. No unexplainable high or low shots either. What I do find strange about your ringing is the fact that it is not completely circular - after all, the excessive pressure would have to be the same everywhere? Assuming an identical resistance of the barrel material, damage should have been concentric.
Are you using LDPE wads? as you're mentioning trapped air, that might be a possibility. I'm using vegetable fiber, and I don't really have trapped air issues.
I do find the powder compression explanation pretty weird though... So BN cases should have it every time, as they usually are compressed very little (and always irregularily) or not at all? And uncompressed charges would be dangerous? Not sure I'm believing that...
FWIW, in the past quite a few experiments were made with front ignition in cartridges, and as far as I know, they didn't have any pressure or ringing issues. We're talking here about a flash tube bringing the primer flash to the base of the bullet, igniting the front of the load. Even Mann in "The bullet's Flight" talks about front-ignition experiments without mentioning chamber ringing.
Also, consider schuetzen shooting with breechseating as such - there is always airspace (by necessity due to the bullet being seated into the rifling, in front of the case) and a wad, yet they don't seem to be ringing barrels?
What I believe is bad is having a wad on your powder column, followed by airspace, and then the bullet - the powder front should never be at a straight angle to the case walls, with air in front. I believe Dell's book 'The Modern Schuetzen Rifle' goes into this matter: apparently he was able to consistently induce case ringing in this way (with nitro, I believe).
I'm very sorry for your barrel, I know I wouldn't be happy with such an occurrence...

[405]

Dang it! sorry to hear that

My understanding of ringing is that it is similar if not the same thing as a bore obstruction.

As far as the burn going far into the charge then moving rearward..... that is one explanation of the theory of detonation with small charges of smokeless and according to Badger can also happen with black.

The bore obstruction theory of ringing. Simply?, as I've understood it, goes something like---- A bore obstruction ring in the barrel is not caused by gas pressure at a point between the bullet and the obstruction. It is caused by mechanical obturation of either the bullet or the obstruction or both at the point of contact between the two. This is Hatcher's explanation and he had a ton of experience with that stuff!! The same or similar could apply in a chamber ring with the wad hitting the base of the bullet.

With blackpowder a certain percentage of the blackpowder remains solid even after firing.... that percentage can be very high--- like 50% of the mass is not turned to a gas. So in a blackpowder ringing.... the bore obstruction is the bullet sitting in the case and the bullet is the portion of the solids in the blackpowder not burned. The solids hit the base of the bullet and one or both obturate outward.... the ring. If the obturation (two solids collision) is concentrated more to one side than the other.... a partial ring.

All theory as I understand it.

[Boz330]

Well I'm going on what I got from Ernie Stahlman, as I said I don't pretend to understand everything that goes on during ignition. What he was saying makes sense to me the way it was explained. I to thought that a ring would go all the way around the chamber, but apparently that isn't necessarily the case. The
40-65 is pretty much a straight wall case, so what a BN case does might be something different entirely. Ernie said that you might do the same thing for 1000s of rounds with out a problem. This isn't my first rodeo so it really caught me by surprise. I don't claim to know everything about reloading BP but I have been doing it for 17 years and this was my first problem. As far as Shutzen, that is mostly smokeless which is another thing all together.
As far as the front ignition I think that the ticket is to not have the powder burning from both ends towards the middle. When he asked me about the high rounds out of the group, I hadn't even said anything about them. I thought that a bad boolit had gotten in the batch although I weigh my boolits+ or- .5.
Fortunately a buddy of mine has a machine shop in his basement and all we had to do was set the barrel back 2 threads to clean up the chamber, still a PIA, but didn't cost me any money. A world of favors to be determined later but no money:roll:.

Bob

[Baron von Trollwhack]

Is it impossible for barrel steel, used by an expert maker, to have a flaw? I have heard of this happening for at least my years. Is that not why a rebarreled action is proofed? BvT

[Don McDowell]

Boz thanks for sharing the information,lots of good food for thought grouped into that . Glad to hear you can get the chamber cleaned up.

[Junior1942]

>We have all been told that that you have to be careful about airspace in BP rounds and I have heard some people say that a little won't hurt anything.

Obviously, a little is all it takes. Every thing I've ever read about BPCR shooting says to leave no air space between bullet and powder.

[Boz330]

Is it impossible for barrel steel, used by an expert maker, to have a flaw? I have heard of this happening for at least my years. Is that not why a rebarreled action is proofed? BvT

This was my first thought when I noticed the problem. Mr Stahlman went into the process that their barrel steel goes through before they even drill, ream., and rifle the blank and it is highly unlikely that there was a flaw in the barrel. Badger Barrels have an outstanding reputation. I was very impressed with the amount of time he was willing to spend talking to me and answering my questions. He called me back after quitting time since he is a hands on owner. My business is the same way so I can appreciate the time spent.
I'm not sure what the tensile of that steel is but it is scary that BP can produce that kind of preasure to basically dent solid steel.

Bob

[Dale53]

Badger barrels are chrome-moly and extremely strong. Charlie Dell was a good friend of mine and we often discussed the phenomenon of chamber ringing. He was the only person that I know of that was able to create the "ringing force" at will (he made up brass barrels as they had less "hoop strength" and he was able to get chamber rings in them at will).

At any rate, Charlie's experiments were for Schuetzen barrels using smokeless powder. However, I believe that the same circumstances would apply to both black and smokeless.

I shot BPCR Silhouette for about 15 years and never heard of anyone ringing a chamber with those loads but I do not doubt for one minute that this did indeed happen.

My method was to drop the powder from a measure and use a compression die. When I set up my compression die, I would arrange for the bullet to compress the powder by .005" AFTER it was compressed by the compression die. That was done to insure that the bullet base was touching the wad firmly (and yet not hard enough to damage the bullet when seating). I used LDPE wads over the powder. I got very consistent results (by chronograph) and minute of angle accuracy.

Ernie Stallman has had world's of experience as both a barrel maker AND a shooter. I would ALWAYS listen to what he had to say.

Dale53

[joeb33050]

I have shot enough fillers and wads to not believe in the various chamber ringing theories.
I've looked for chamber-ringing stories, and have noted a common denominator-the new barrel.
A good gunsmith once told me that he didn't believe in any of the chamber ringing theories, believed that rings came from a reamer/chip event while chambering.
I've read C. Dell's work on chamber rings more times than anyone else on the planet, and do not find it convincing. No disrespect, just far from convinced.
I can shoot and have shot thousands of shots with a Dacron wad, never a ring.
I suspect that the barrel chamber was scored before you fired a shot.
joe b.

[Boz330]

Gert, I don't use LDPE wads. I use a .025 pressed paper wad.

Joe, trust me that chamber was perfect after reaming. The reamer was brand new. I noticed the problem on the brass initially. I had brass that had been fired through the same chamber that was not marked. There were several hundred rounds through the gun before the ring showed up, so it wasn't a product of the initial chambering. The ring is visible with the naked eye and would have been hard to miss in the original chambering in any case.
I to have fired a pile of smokeless loads with dacron wads and had no problem. In fact I fired a lot of smokeless and dacron in the original barrel on this gun before going all BP all the time.

Bob

[felix]

Joe, use some other filler (more firm) and you will change your mind. Yes, cases have rings implanted into them from reamer action. You can always see them after shooting full power loads on a new barrel. ... felix

[martinibelgian]

Bob,

This one has me stumped - to be honest, I don't find the Badger explanantion of what happened satisfactory (we should then see a lot more rung chambers IMO), but I too am at a loss for what did cause that chamber damage visible in your pics - especially as that blister is pretty weird.
OTOH, why should this only happen with BP and not with smokeless? BTW, Schutzen today is mostly smokless, but don't forget the history, when all schuetzen shooting for a long time was BP exclusively, up to the beginning of the 20th century.

[August]

I have experienced a rung chamber, so I believe what Boz (and Badger) is saying. I guess you other guys will be believers when you've seen it for yourself. Unless....... you choose to benefit from Boz's experience.

[runfiverun]

the dacron will ring a chamber also, it is just at the neck end.
ringing is caused by something slamming into another, be it a pressure spike in the middle, or dacron hitting the base of a boolit .
this is like "see", it don't happen. but when it does it is pretty obvious.

[405]

Bob,
I didn't think of it earlier but if it makes you feel any better ringing may be more common than most folks think or admit. I've looked at a fairly large number of old, original BP cartridge chambers and many have a slight ring in the chamber where a "normally seated bullet base would be. A good bright bore light into the muzzle with a mirror near the breech gives the best view. With the bright light at a very shallow angle or nearly parallel to the wall seems to show all chamber imperfections. I always just thought of it as a "peening" thing at the bullets base. Most I've looked at really don't affect the function of the rifle. Some may have been there for 100 + years???? Most appear to be very shallow and generally go un-noticed if not looking closely in that area. They usually look like a shiny ring but do have a very shallow depth if studied long enough with the right light angle.

Anyway, glad to hear there is an "easy" correction for your gun.

[Boz330]

I actually shot the gun most of the season with the ring. It didn't affect extraction at all. As near as I could measure the casing the blistered looking area was about .001 and the other area was less. In fact Ernie Stahlman said to just shoot it. It did not seem to have any effect on accuracy.
I got the gun back over the weekend and our last match of the year is Saturday so we shall see. I'm going to have to bust my butt to get ready since I don't have anything loaded or even any boolits cast.

Bob

[BPCR Bill]

Bob, sad to hear about your barrel. I know we've all been told of the hazards of chamber ringing and how to avoid this pitfall, but now I see SPG penned an article in "Cranks Corner", Black Powder Cartridge News, Summer 2008, adressing breechseating and black powder in Schuetzen rifles. He does have a point, Charlie Dell had managed to ring chambers at will with smokeless loads, but apparently he couldn't make it happen with BP. Garbe alludes to tests done by Springfield Armory that have the same results, no chamber ringing with Black. I have breech seated boolits and fired with black (38-55) and have had no adverse effects, except accuracy issues, until I got the seating depth just right. As far as my normal BPCR loads in the 45-70 and larger, I allow no airspace, but dependent on the powder used, I can go with no compression to as much as .10". As noted, your anamoly isn't a true "ring". This is going to be a matter of discussion for sometime I imagine.

Regards,
Bill

[DonH]

. I called Badger and talked to Ernie Stahlman who was very patient with me in his explanation of what might have caused this. I am going to try and explain this as close as I can remember his explanation.
....His explanation was that ....sometimes the fire will go to the side of the case were the powder may not be compressed enough and burn up the side of the case in looser powder and then burn back towards the center, or towards the flame coming up from the bottom. When this happens the preasure really spikes causing the high boolit strike.

Bob

Huh?

Now I respect Mr. Stallman for his BPCR shooting knowledge and barrel-making prowess. However, the inquisitive side of me pokes up its head here and wonders, "How can he know this is happening? And if it is happening, how can the presence of this 'burn phenomena' and effects of any resulting pressure spikes be verified?" I'm not saying the phenoma does not exist - just harking back to the college physics lab and wondering how can one definitively prove it? I think it would take extensive testing of both interior ballistics and metallurgy.

Two things came to mind when I read the post and looked the pics: (1) as has been noted previously, why would the expansion occur at specific points rather in a uniform manner? It seems to me that if the extra-normal expansion occurred at a point rather than uniformly it would indicate a weakness in pressure containment at that point. And (2), since Mr. Stallman does not make the steel bar from which he makes his barrels, a problem COULD exist in a blank and escape detection until proofed (fired). (Here the advantage goes to the proofing of every barrel/firearm rather than being proofed by the customer after taking delivery of a firearm.)
I have a Remington barrel about fifteen years old which through a Hawkeye bore-scope is a very smooth barrel except for a short section one land which is missing.
The only apparent explanation for the missing chunk of land in the Rem barrel is that an inclusion (impurity) existed in the steel which was only "uncovered" but rifling of the tube. If such an inclusion existed in a steel bar and after boring/reaming/rifling was left with only a very thin layer of steel left over it, at that point the barrel steel would not react with the normal elasticity to the pressure resulting from powder ignition. If this happened, to say, "that was just a faulty piece of steel" and replace it would not be a reflection on a barrel maker.

As to air space, fillers, etc. and rung chambers, I'm not an expert on this either. But there seem to be a good many references to loading with air space in the "old days" when barrel steels were much less strong and without apparent problems. A practice this subject makes me think of is that in loading BP military ammunition the British used carded wool to take up space between powder and wad or bullet. Since the wool is not a solid, does anyone doubt the existence of air in the loaded cartridge? This was done in the Snider round which was loaded in coiled brass cases and fired in (initially) wrought iron barrels. I have not read of rung chambers being a normal occurence in this instance.

[martinibelgian]

To be honest,
this explanation doesn't convince me either - and I'm glad I'm not the only one. Certainly as there were quite a few experiments done with front iginition, and none of these reported anything on chamber ringing. I'd rather go by the steel thing...

[Boerrancher]

For years before the Belted Magnums caught on, people were using a dual primer system on 30-06's that would cause ignition of the power from both ends, to get slightly higher pressures for long distance shooting. I never read or was told that there were any problem with ringing of chambers. I am not exactly buying the explanation either. I don't see how a barrel that is suppose to be proof tested to 80K psi, can be damaged by a 36,000 psi charge. I do understand how chamber obstructions can, and if the load was assembled in this way: powder, wad, airspace, boolit, then yes there could be a ring. I have never known of anyone who knew what they was doing with a muzzle loader compress their powder. They always pushed the ball down to where it was just touching the powder. This would allow the powder to remain somewhat loose, and according to the explanation that was given to Bob, would allow for a burn up the side and then a burn in both directions causing a ringed chamber in a front stuffer. This would theoretically happen several times over the course of the muzzle loader's life and therefore eventually lead to something that would be quite obvious to the shooter. Also Black powder doesn't really burn as much as it detonates, which is why it is classified as an explosive rather than a propellant. It is a low explosive but an explosive none the less. The only way I can see Black causing a ringed chamber is if there was an air space between a wad and a boolit.

Best wishes from the Boer Ranch,

Joe

[Kenny Wasserburger]

I am of the Opinion, remember its just that, That the problem is more then likely an inclusion in the steel that showed up after fring a few rounds and finally showed up. A true ring would of been around the entire case.

A am glad to hear setting the barrel back a couple threads did the trick. Best of luck to you.

The Lunger
Kenny Wasserburger

[Boz330]

If it was an inclusion in the metal then there is a possibility that it will show up again since all we did was move the barrel back1/8". On rechambering there was no break thru into any sort of void. Since I clock my brass it won't be hard to figure out if it does happen. I was TOLD that the barrels blanks were inspected which I would assume was some sort of xray inspection for problems. Might be they were just trying to get out of replacing a $250 barrel. Seems like poor economics to me though.
What made me suspect that Mr Stahlman knew what he was talking about was that he described issues that I didn't relate or even think were related to the problem. BS???? I don't know, but if that was the case why spend the time to try to explain it to me. Just say you screwed up and sorry about your luck.
I don't pretend to know about or understand internal balistics, but on another board that I follow there was an explosives expert that occassionally commented. His company was involved in the dirty tricks operation were 7.62X39 ammo was manufactured to blow up commy weapons. The ammo was supposed to be integrated into discovered ammo dumps to blow up weapons and create morale problems among the VC. The out come was they used C-4 but before that, they actually used BP and it worked. They thought that not killing everyone in sight would be more demoralizing in the long run. I tried to locate that post but couldn't find it because the search funtion on that board is only good on the current page. The point is that BP can be more dangerous than we sometimes think under certain conditions. I think that my problem was a combination of trapped air under a well lubed boolit with tight slip fit and a preasure spike. You don't have to beleive it if you don't want to. It's no skin off of my nose one way or the other. I've gone to some compression on Swiss and neck tension on the boolit and that seems to be working for me and while groups are not completely as good as I think possible, I shot my personal best ever match with it on the 11th.[smilie=w:


Bob

[Lead pot]

I rung two barrels and put a walnut in a fine slug gun barrel from a short seated linen patched smooth walled bullet(PP type bullet)
The first was when I was very young and first started loading.
I just used a 1/2 case full in the .43 Spanish because of the recoil and fired many many rounds that way and never had a problem till one day I couldn't extract the empty case.
The last one was with a long .45 case loaded with a compressed case and it had a hang fire, a very short time span like a flint lock going off.
I cant blame these on flawed barrels or bad cases, just my screw ups except the one.
I can happen and will.

[DonH]

Ringed chambers do happen. Thing is, this gentleman's chamber did not (from the photos) have a ring; rather it appeared to be slight bulges at specific points. Powder burning in a cartridge case is not a shaped charge applying pressure in a specific direction. One would think the pressure would try to act equally in all directions, which apparently is why a "ring" occurs.
I caused a ring or "walnut" in a barrel once. A missing powder charge in a .45 ACP round left a bullet stuck in the barrel. Next to last round in the magazine in a rapid fire string. The subsequent shot blew the stuck bullet out and they both hit the target at 50 ft. The damage to the barrel a full ring.

Regarding my earlier post, again I am not really disputing Mr Stallman's explanation. I would just like to know how his ignition theory can be proven. Maybe really high tech lab ahs sthe ability to prove this. Or NASA. Also, I have no doubt about Badger's inspection process but I do know that in making anything imperfections can and occasionally do get passed inspections. And I know that pressure from burning propellants is nothing to be cavalier about.

[cajun shooter]

Boz330, You are correct about the AK ammo. The idea at the time was good. It was to have them too scared to shoot the weapons for fear of them blowing up. It was told to me by a GB who went on some of these missons. But as the old saying goes "TOO LITTLE TOO LATE"

[DonH]

This is a bit OT but since it was brung up in this thread, I would like to know how one could get enough black RIFLE powder in a 7.62x39 case to make sufficient pressure to blow up a rifle so chambered. A highly compressed charge of BP in a typical BPCR round would be very hard pressed to top 30,000 psi. An AK round goes 45,000 psi or more. What I could believe is the use of one of the MEAL GRADEs of black powder such as are used in fireworks or like the old black blasting powder. These are very finely ground (like dust) and when ignited burn completely instantaneously creating tremendous pressure.
Last I looked Powder Inc. showed these grades of BP on their site and there the difference between black sporting (rifle) powder and meal grades is readily seen. A case full of one of these very fine grades of BP in almost any cartridge would make a mini bomb. My dad tells of a guy in the community where he grew up, due to scarcity of sporting ammo during wartime, reloading shotshells with "blasting powder". His shotgun was wrecked.

[Boz330]

It has been several years since I read the post but I thought that it might have been 4F which is not recommended for anything but priming. The fines out of powder that isn't graded very well will go thru a 4F screen like you know what thru a goose.

Bob

[BPCR Bill]

Boz330, You are correct about the AK ammo. The idea at the time was good. It was to have them too scared to shoot the weapons for fear of them blowing up. It was told to me by a GB who went on some of these missons. But as the old saying goes "TOO LITTLE TOO LATE"

Correct, there was an article on that in American Rifleman several months ago. "Operation Eldest Son". It wasn't confined to AK ammunition either. The spooks would doctor mortar rounds, and artillery rounds as well.

Regrads,
Bill