Can An Uncapped Rifle Go Off?

[MikeyB]

I'm sure anything's possible, but practically speaking, can an uncapped Enfield or Springfield accidentally go off? While the operator is ramming home the round for instance, in the thick of battle, surrounding fire and explosions, heat, can/did rifles ever go off uncapped and take off the poor soldiers hand?

 

[captaindrew]

Very unlikely but yes it can happen if there was a hot ember in the barrel. That's why you keep the spent cap on the cone till after you've reloaded to keep the air from rushing in. Priming is always the last step in percussion rifles. I've seen it happen once in reenacting where the powder charge went off while loading, luckily with no injuries but it was a scary moment.

 

[MikeyB]

Very unlikely but yes it can happen if there was a hot ember in the barrel. That's why you keep the spent cap on the cone till after you've reloaded to keep the air from rushing in. Priming is always the last step in percussion rifles. I've seen it happen once in reenacting where the powder charge went off while loading, luckily with no injuries but it was a scary moment.

How does the cap work exactly? I always thought it was just creating a spark that ignited the powder. How does the airflow fit in?

 

[OleMissCub]

How does the cap work exactly? I always thought it was just creating a spark that ignited the powder. How does the airflow fit in?

The airflow can give life to an ember inside the barrel (think about how you breathe on a little fire to make it grow). So let's say you fired your rifle and are re-loading: the first thing to go down the barrel is the powder. If for some reason there is an ember down there it could ignite the powder.

You never realize just how hot these rifles can be until you fire them a bunch. You fire 20 shots through a muzzleloader and you really have to avoid touching the barrel to keep from being legitimately burned.

 

[JeffFromSyracuse]

The airflow can give life to an ember inside the barrel (think about how you breathe on a little fire to make it grow). So let's say you fired your rifle and are re-loading. The first thing to go down the barrel is the powder. If for some reason there is an ember down there it could ignite the powder.

You never realize just how hot these rifles can be until you fire them a bunch. You fire 20 shots through a muzzleloader and you really have to avoid touching the barrel to keep from being legitimately burned.

Is there mercury on the cap to further prompt a chemical reaction?

 

[OleMissCub]

Is there mercury on the cap to further prompt a chemical reaction?

Something like that. I'm not exactly sure all the chemicals that are on a musket cap, but it definitely has something on it that helps create the spark that goes into the barrel. They are remarkably reliable in my experience.

 

[bayonet]

The airflow can give life to an ember inside the barrel (think about how you breathe on a little fire to make it grow). So let's say you fired your rifle and are re-loading: the first thing to go down the barrel is the powder. If for some reason there is an ember down there it could ignite the powder.

You never realize just how hot these rifles can be until you fire them a bunch. You fire 20 shots through a muzzleloader and you really have to avoid touching the barrel to keep from being legitimately burned.

That's the risk with almost any firearm if you fire a lot of rounds at once thru it. Had rounds cook off in M-16s and M60s because the barrels were so hot. Couldn't get the 2 barrels to cool down even with a barrel change on the M-60, nothing like a bright red cherry barrel.

 

[BillO]

Very unlikely but yes it can happen if there was a hot ember in the barrel. That's why you keep the spent cap on the cone till after you've reloaded to keep the air from rushing in. Priming is always the last step in percussion rifles. I've seen it happen once in reenacting where the powder charge went off while loading, luckily with no injuries but it was a scary moment.

I used to shoot N_SSA and it wasn't that uncommon.

 

[captaindrew]

How does the cap work exactly? I always thought it was just creating a spark that ignited the powder. How does the airflow fit in?

The air can flow in the same hole the spark goes through. Same as on a cannon where one of the crew has to keep his thumb on the primer vent while reloading to prevent air from rushing in.

 

[Rhea Cole]

Black powder is remarkably stable. Even today, it is used as the initiating charge for modern explosives. It requires heat to ignite. Shock will not set it off. That is why it can be milled to various grain sizes. Black powder can get soaking wet & still retain its explosive potential after drying out.

Throughout the centuries of black powder warfare, charges poured into over heated musket barrels would flash. This was certainly exacerbated by lingering sparks on the barrel. On the other hand, a charge seated in a cold, clean breach with cartridge paper tamped on top cannot spontaneously ignite.

Caps are coated with fulminate of mercury. As many of us can attest from our childish mad bomber phase, it is not hard to make. Unlike black powder, the slightest impact will set Fulminate of mercury off. Mere jostling in a cap box is not forceful enough to set it off, making it ideal as initiating charge for a musket.

Absent an electric spark, open flame, or extreme heat, black powder will not ignite.

 

[Craig L Barry]

Modern percussion caps do not use fulminate of mercury any more, but the point is the same about black powder needing a spark or flame to set it off.

 

[FedericoFCavada]

I think the question has been answered, but yes, uncapped rifles can "go off." Black powder produces lots of fouling and residue. Some of it stays very hot. On a percussion gun, the hammer/cock stays down on the just-fired percussion cap, sealing the cone or nipple. Thus, no air can flow through the priming ignition hole to the chamber. I have seen a so-called "cook off" with a muzzle loading firearm. The hammer or cock was down, but whatever was in the lube for the Minie balls may have been a factor? Certainly it was really hot from repeated firing at speed, and it was Texas, so a hot day. It was not very humid either, which may have been a further factor. The person it happened to had to go to the hospital and have some skin on his hand abraded. Most unpleasant. Always keep your rifle pointed away from you when loading.

Historically, the "casting about" of the musket or rifle musket placed the musket with the ramrod channel towards the loader/ firer. This ensured that not part of the hand would be over the muzzle when drawing or returning the rammer. It also kept the bayonet away from the user, to avoid injury while working above the muzzle. When the rammer is returned to its channel, the pinkie/ little finger is used, thus keeping the more useful digits out of the line of possible fire from the muzzle.

If you compare muzzle loading artillery to rifles, as was done up post, you get the difference in procedures: In artillery, a thumb-stall is pressed down over the touch hole, blocking the ingress of oxygen into the barrel. This is done sufficiently that it forms a vacuum noise "pop" when the sponge comes out of the barrel. A worm scours the inside of the barrel, and hopefully snags any smoldering piece of a cloth powder bag or cartridge that might be in there. Then the sponge goes in, and dampens the barrel, puts out any smoking debris or fouling or whatever, and softens what fouling is still in the bore. Only then is the new cartridge or powder charge introduced. In a shoulder arm, you are just relying on there being minimal air inside the bore, and anything burning to exhaust the available oxygen and put itself out.

I'll also point out that there are double flaps on most cartridge boxes and also on very many cap boxes too. Water-resistance against rain was improved, but then so too was projection from errant sparks, I'd wager...

Keep your powder dry! Stay safe.

 

[bayonet]

The air can flow in the same hole the spark goes through. Same as on a cannon where one of the crew has to keep his thumb on the primer vent while reloading to prevent air from rushing in.

Yup how many Artillerymen lost an arm when the piece went off while they were ramming the barrel. Ouch

 

[DixieRifles]

I have seen a so-called "cook off" with a muzzle loading firearm. The hammer or cock was down, but whatever was in the lube for the Minie balls may have been a factor? Certainly it was really hot from repeated firing at speed,

Reenactors who shoot Artillery will usually roll their powder charge in Aluminum foil. It is easier to built this than using a bag. However, I've been told, there is danger in these "cooking off" if the cannon has been fired repeatedly.
I talked to an owner of a replica breech loading Williams Gun cannon and asked him how many times could he fire it in 1 minute. (Historical accounts said 20 rounds). His answer was: 8— after that the barrel is too hot and could blow up in my face when I load the next round.

Ive never worried about a round going off while loading rifle or pistol. But I resist the urge to place my face over the muzzle.

 

[Rhea Cole]

Modern percussion caps do not use fulminate of mercury any more, but the point is the same about black powder needing a spark or flame to set it off.

Right on, I am stuck on the 19th Century, Thanks for the correction.

 

[FedericoFCavada]

Reenactors who shoot Artillery will usually roll their powder charge in Aluminum foil. It is easier to built this than using a bag. However, I've been told, there is danger in these "cooking off" if the cannon has been fired repeatedly.
I talked to an owner of a replica breech loading Williams Gun cannon and asked him how many times could he fire it in 1 minute. (Historical accounts said 20 rounds). His answer was: 8— after that the barrel is too hot and could blow up in my face when I load the next round.

Ive never worried about a round going off while loading rifle or pistol. But I resist the urge to place my face over the muzzle.

The times I've fired off a mountain howitzer, that has been the procedure: a powder charge in aluminum foil. The crew follows the modern safety procedures, tipping the barrel to maximum depression, holding a thumb stall over the vent for the required amount of time, then the wormer, the sponge, etc. etc.

Similarly, in skirmishing, we never "thumb" the ball down the muzzle of the musket... Just hold it at the sides and place it in the muzzle, then use the ramrod.

 

[Rhea Cole]

Regarding the traumatic amputation of #1's right arm by premature detonation, the earliest example I have on file is a Portuguese man who not only lost his arm, in addition he was flung through the embrasure & fell 45 feet into the ocean. A gaudy example from more recent times was at Ticonderoga State Park. A reenactor gun crew was rapid firing when a charge went off when rammed home. The head of the sponge rammer struck a man sitting at a picnic table with his family about 75 yards down range. During the Civil War, soldiers home on leave rapid fired a cannon on a town square. A premature detonation mangled #1 & the sponge rammer killed or maimed spectators.

The common thread that unites all of these casualty events is rapid fire. The manual is very pointed when stating that no more than one shot per minute should be fired. In practice, where the gun had to be rolled back into place & aimed, three rounds in a minute could be fired in a pinch. The kind of wild flailing rapid fire seen at re-enactments has nothing to do with routine military practice. (No disparagement intended, it is just a fact.)

Parks Canada did extensive tests of how long a substance would continue to smolder on a cannon barrel. After 7 minutes, everything tested used up the available oxygen & was extinguished. NPS regulations require 10 minutes between shots. Since 1960 there have been no injuries from premature detonations. Sadly, hardly a year goes by without a casualty or death due to rapid firing cannon outside the NPS system.

I am an NPS certified gunner, so am responsible for the safety of my crew & visitors. I also train new crew members. The traumatic amputation by premature detonation is a central part of my safety lecture. I have three priorities, safety, safety, & safety. Everything else comes after that.

 

[FedericoFCavada]

"palms up and thumbs facing away from the muzzle" on the sponge/rammer, yes?

My gun captain urges putting the "thumb stall" on the little finger and ring finger, not the actual thumb. Loss of an opposable thumb being a bigger issue than some of the rather more superfluous digits...

 

[Rhea Cole]

"palms up and thumbs facing away from the muzzle" on the sponge/rammer, yes?

My gun captain urges putting the "thumb stall" on the little finger and ring finger, not the actual thumb. Loss of an opposable thumb being a bigger issue than some of the rather more superfluous digits...

The thumb of #1's right hand must always point toward the sponge. When ramming, face down range, point left hand toward the offside trunnion & bend the left knee. That not only uses the momentum of the body to move the round, but naturally keeps it away from the muzzle just in case.

The reason for keeping the thumb pointed toward the sponge is ergonomic. Should there be a premature detonation the hand in that position naturally let's go. Facing toward the rammer head, the grip naturally locks, resulting in traumatic amputation. In the CW light artillery drill, #1 uses his right hand to manipulate the sponge rammer, not two hands as seen at re-enactments. They use a very different drill.

500 hundred years of trial & extremely painful error created the CW cannon drill. With the thumbsal on the thumb, the elbow cocked forward it securely seals the vent & allows the gunner an unencumbered view of the front sight. I see no point whatsoever to change that. Of course, re-enactors do not follow the historic drill & do not (in my experience) place the pendulum sight in place between shots, so the pinky finger could serve the purpose. I am too fond of my right arm to serve a gun without a securely stopped vent.

Historically, #3 places his palm over the vent to keep the friction primer secure. That was a left over from firing with slow match. It kept the priming safe from wind & dry. I know a man who, in an excess of authenticity did that. #4 stumbled on a may pop vine & shot the primer & a jet of plasma through the web of his thumb. Fortunately, no bones were hit, but he has a very decorative scar.

You probably know all this, others who read this thread don't.

 

[OleMissCub]

Good post. Drill manuals are written the way they are for a reason. Their method of cannon drill isn't a mere suggestion, but rather it is a definitive conclusion based upon exhaustive study of the most efficient and safest ways to operate a piece.