blank load detonation

[matt denison]

A barrel bursting from a blank load is not new, it has happened before. Here is the theory on why:

After a few blank loads have been fired from a gun, in this case a musket, the fowling builds up in the barrel because there is not enough pressure to burn the powder cleanly or efficiently. Also because there is no wiping effect from shoving a PRB down the tube. When a load of powder is dumped down the barrel some of it sticks to the barrel walls for the length of the barrel. When the gun is touched off this loose powder will burn faster than the charge at the breech, causing a detonation rather than a controlled ignition from the breach end. Since many or most reenactors aren't allowed to carry their rammer onto the field of battle there isn't a chance to wipe the bore between shots, creating this situation. The best you can do is keep your charge at a minimum, bang the butt on the ground to settle as much powder as you can into the breach area. Limit how many shots you take before wiping the bore.

That's the theory, that's my advice. take it for what it's worth.

LDog aka Matt Denison

 

[roundball]

:hmm: haven't yet heard of a blank load bursting a barrel...but if they do, I'm not convinced what you theorized would be the failure mechanism...might be...but for example, here are two questions:

1) If the powder in the breech hasn't burned all the way to the top of it's mass, how would flame get past that powder in the breech to ignite the kernels of powder that may be clinging to fouling on the bore walls...without first or simultaneously igniting the rest of the powder in the breech?

2) And if the scattering of kernels at points along the bore walls could somehow ignite before the breech powder finished burning to the top of it's mass, what would acctually be the failure mechanism that would occur that would cause a barrel to burst?

 

[spottedpony]

I'd add to this, my question being, that barring a bore obstruction of some kind pressure would vent out the end of the barrel wouldnt it? and if fouling were so bad to create a bore obstruction, wouldnt that prevent powder from reaching the ignition area of the bore the same way as a plugged nipple or vent prevents ignition?

 

[Tumblernotch]

While I haven't seen or heard of a blank bursting a barrel in many years of reenacting, I wouldn't discount the possibility. I do know from experience that a heavy blank load fired with the muzzle pointed skyward will cause some unexpected and very undesirable things to happen.

I was using some pretty heavy loads in a Whitworth at a reenactment in Virginia some 20 years ago. At the end of Sunday's scenario, we were instructed to "duck hunt", which was a term we used to describe elevating our pieces and firing them to clear any unfired charges before moving off the field. We always did this for safety purposes. Forgetting I had a fairly heavy load, I elevated and fired. The result was a blown back hammer, a ding in the stock and a broken tumbler. I had forgotten that the pressure would be higher and never thought that a blank load's pressure would spike so dramatically. And I'm sure that the built up fouling didn't help matters any. Even back in the days when we could use our ramrods, we never tried to wipe during a battle. We either didn't have the time or we were afraid that we would hang a ramrod in the bore and have to sit it out until we could get it removed. I personally believe that fouling won't cause too many problems if the weapon is cleaned between scenarios. Most CW reenactments have events on both Saturday and Sunday. If the musket is cleaned Saturday night, that will alleviate much of the problem. We had one guy in our outfit that barely managed to clean his musket between reenactments. He often had trouble just getting it to fire and on at least one occasion, he had an ember smouldering in his breech and had a round cook off when he put it in. Luckily, he didn't have his face too close to the muzzle. After that, those of us who had ordnance duties, especially our Ordnance Sgt., really started coming down hard on those who slacked off in caring for their weapons. Between us and the general tightening of the rules, this problem soon disappeared in our ranks. I don't know how well they do it now, but can only assume that it is pretty strict, at least in the major events.

 

[roundball]

Forgetting I had a fairly heavy load, I elevated and fired. The result was a blown back hammer, a ding in the stock and a broken tumbler. I had forgotten that the pressure would be higher

OK, I'll bite: Why would the pressure be higher shooting a blank load straight up??

I've shot my .62cal Flint smoothbore with heavy powder & shot hunting charges straight up at crows passing overhead and never had anything different happen.

 

[paulvallandigham]

I agree with Roundball: When you point the barrel to the sky, all you are adding is the "pressure" of gravity, which is something like 14 lbs. per square inch. That cannot be enough added pressure to amount to Much of anything. And, since the gases are free to pass up and out of the barrel. IN a 69 caliber barrel, that extra pressure amounts to 5 lbs more pressure on the load. There has to be that much variation in pressure just from one shot to the next.

I really suspect this seam was either open, from the beginning, or cracked from repeated heating and cooling from prior shooting. I don't think the low pressure generated even from a large powder charge would split open a properly welded barrel, and if it did, it would not be at the weld.

 

[matt denison]

One more time. The fouling is not causing an obstruction in the barrel. Pressure has nothing to do with it. It's called detonation. Happens in some ultra-light pistol loads too. Ask some Cowboy Action guys about it. Chances are they've heard of it happening with pistol loads that are too light.

Detonation occures in the musket barrel because ALL of the powder is blowing simultaniously for the full length of the barrel causing a shattering blast that will exploit any ever-so-slight defect or flaw in that barrel. The worse the detonatiion, the more likely that it will blow the barrel. There isn't necessarily a "charge" at the breach for the flame to have to blow through because a large percentage of the powder "charge" is distributed along the length of the barrel. In the case of the musket in the previous thread the fellow was using 110 grains of powder: a good stout load IMHO. This subject is something that I have discussed at length with others who have seen the phenomenon (sp) and have tried to back in to whatintheheck happened.

An under charged .45 Colt with say, only 2 gr. of Bullseye has been known to blow the cylinder of a Ruger to smithereens. This is part of the reason that Coyboy loads often have a Dacron wad inserted in them to hold the powder in a bunch near the primer. If you read Guns & Ammo Mag. or Cowboyguns Mag. (from our friends at SASS) you might have heard of this. True fact, it happens. You have to be careful.

Matt

 

[Grizzled Roberts]

I don't know guys. After looking at the pictures
it was a cheap-o gun. The breach plug looked like a cap instead of a screw in. The barrel rupture is as streight as an arrow. This sure looks like a seam to me! If he had fired a round ball in this gun it would have become a hand grenade!
I have an older India musket an 1816 repo. I have shot over a hundred rounds from it with no problems. ( only had it a couple of months! )It's barrel appears to have proof marksbut I may check the breach plug before I shoot it again. If its got a cap it may become a sawed off wall hanger!
:thumbsup:

 

[Mike Brooks]

The breach plug looked like a cap instead of a screw in.

I believe they are all made that way. Why I don't know.

 

[Va.Manuf.06]

.......
I have an older India musket an 1816 repo.... It's barrel appears to have proof marksbut I may check the breach plug before I shoot it again. If its got a cap it may become a sawed off wall hanger!
:thumbsup:

Some advice - your repro M1816 has "reproduction" proof marks, they mean nothing. They are just there because they were there on the original. If I were you I would pull the plug and check the threads. If you don't have the proper tackle to do the job yourself, have it done by a qualified gunsmith.

 

[Deadeye]

Matt, what you're saying is simply not true. Not true about detonation in black powder guns and not true about light charges ever blowing up a single action. Occationally someone does blow up a gun and they try to blame it on something besides themselves but it has always proved to be
from double, triple,quadruple charges and sometime of the wrong powder. Ballistic engineers have been trying to produce these detonations in the lab for at least 50 yrs. and all say it can't be done and there is no such thing as a detonation
with the amount of powder we're talking about here.

 

[Viclav]

Gentlemen,
My first post here. I have no experience with muzzleloaders beyond cap n' ball pistols, and certainly none with flinters. I did acquire an abused but genuine India Pattern Bess a while ago, and have often wondered about using one of these new-manufactured Indian guns as donor for parts, particularly the barrel, hence my interest. I seem to recall old threads (from this forum?)indicating that significant irregularities in the breech-plug to barrel design and fit had been encountered in one of the "big three" India seller's offerings...such that powder might accumulate in the plug threads over time. Could this have caused the failure under discussion? Humbly submitted,

Victor

 

[matt denison]

Deadeye, look at the picture. That barrel didn't just rip down the seam, it expanded forcefully enough to shove the underlugs down and shatter the wood. The breechplug sheared off from the force of the blast. This isn't a simple rupture, it is a catastrofic failure. An obstruction causes a much different profile, including but not limited to, a bulge and usually pieces ripped from the barrel, and/or a "banana peel" effect. This gun blew from a blank load. Do you have a better expalnaition? Detonation is not like UFO's or gohsts. They happen, I'm only trying to warn the public how to avoid it happening to them. (my apologies to you if you believe in UFO's and gohsts)

Matt

 

[xxgrampa]

greetings l dog,

the same thing happened with the big over bore cases in smokeless rifles. ie 7 mag.

the powder in the ml ignites in the back of the bbl. the flame overshoots the charge and then ignites the front of the charge. now you have the charge burning from the front and the back. when they meet, there is a tremendous increase in pressure. something has to give..

you are absolutly keerect, detonation is nothing new, it's been around and known about for a loooong time..

..ttfn..grampa..

 

[burgessrudy]

The previous post raises a Question I have had. If the touch hole is drilled so that it is close to center of say a 110Gr charge, how would it burn? All at once? In two directions at the same time? Or only from the center to the front?

Did the touch hole allow a release of pressure as it normally does on every shot by having the main charge exit back out of the touch hole?. Did the Flash Guard stiffle the release of energy and pressure for a split second that caused the build-up of pressure in the barrel?

 

[paulvallandigham]

Neither a vent, or flash guard would create the kind of pressure needed to rupture a good barrel. The flash guard is so far from the vent that there is no way it could build enough pressure. The vent, even when plugged is going to clear and allow pressure to be reduced and gases vented no matter what. The problem with blank charges is that we don't know what kind of powder was actually put in the barrel. If, for instance someone actually used FFFFFFFg powder( flash powder) or even FFFFg power( priming powder) in the barrel, in a substantial amount, the pressures generated would be substantial. Again, a good barrel would withstand them, But a barrel made out of seamed pipe, that is suppose to be welded together, but may not have been, will give way as this one did, even with a heavy charge of FFFg powder. If there was any kind of bore obstruction, it will be apparent from the physical appearance of the barrel remains.Factories have regularly done destructive testing of their barrel, to see what it takes to rupture them. Some of the rest of us have our own experiences with " destructive testing". Some of it was planned, and some wasn't. But the cumulative knowledge about such barrel failures tells us that some things just can't happen the way folks want us to believe happened. I have engaged in destructive testing as a lawyer to show another lawyer that his clients injury could not have occurred in the way he is describing, by showing the lawyer the events can not be duplicated in a controlled test. That is, we can create the condition of the firearm the way the client describes it, but that does not cause the failures or injuries that are similar to what the client claims happened to him. I was " Myth busting " years before the TV showed aired. It actually is done in crime labs, and by defense attorneys all the time.

 

[CoyoteJoe]

Laffindog does have a point here. I don't know if the phenomenon of detonation ever has or could happen with black powder but it does happen with smokeless, always with lighter than normal loads. For most of a century the powder makers refused to believe it because they could not duplicate it in the lab. They insisted it must be reloader error, a double charge or the wrong smokeless powder. But it has happened to people who didn't own any "wrong powder" and in instances where the cartridge would not hold a double charge or where the firearm could have withstood a double charge. It has happened in instances where the same firearm has safely fired hundreds or thousands of rounds with the same load and no unusual happenings until suddenly the gun blows for no apparent reason. We now see warnings in reloading manuals with some powders saying "do not reduce this load".
How this happens is still not understood because, as Paul said, it can not be reproduced in the lab. Perhaps it is some freak combinations of how the powder lays in the case, perhaps some contaminate of oil or dirt in the case, perhaps some powder getting inside the primer, perhaps some combination of many factors. But it has happened with loads that were safely fired thousands of times. That is why it can not be reproduced in the lab, it is a "one in a million" happening and no one has tested a million cartridges in trying to reproduce the effect. It is NOT TRUE that the cause has always been traced to reloader error. In the vast majority of these instances no attempt was ever made to trace the cause, it is just too easy to say "reloader error".
We simply do not KNOW what actually happens inside a gun barrel. We have an operating theory which seems to work 99.999% of the time but there is still that rare occurrence which does not fit the theory. Since it does not fit the theory we simply write it off as shooter error, even though that does not fit the theory either.