Rung Chamber

[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.


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