From whence the myth of the dangerous air gap?

[MikeJackmin]

This is speculation, but I suppose there might be an issue with the front of the unburned powder column slamming into the stationary bullet.

There was a thread on the autoloaders section a while back asking what would happen if a standard 1911 pistol were fired when there was an obstruction holding the bullet in place. What happened (much to my surprise) was "not much"; however, the person performing this experiment was careful to explain that if the bullet were allowed to move, even a little, then the effects were likely to be much more dramatic.

Half a powder column would not weigh much, but it could be moving pretty fast when it hits the bullet. I wouldn't discount the possibility that it could cause some damage.

 

[Bill M.]

I do not care if it is a myth or not. I am not about to leave a gap. Unless my patent breech causes one?

 

[Loyalist Dave]

From the 1880s through the first world war, schuetzen competitors frequently breech seated bullets, either loading from the muzzle end, or using devices to do so from the breech end. Breech seating means that the bullet is not just loaded into the lands, but is sufficiently far into the barrel to fully engrave and thereby seal the bore. There are accounts in old timey gun rags of chaps thus seating bullets as much as 3/8" ahead of a case mouth full of black powder, albeit often with a few grains of pistol powder to duplex the load and promote cleaner burning. Roberts, De Haas, Sharpe and others all discuss the process and none of them, nor contemporary gun rags, discuss the terrors of the dreaded air gap.

Why?

Because things have changed, and the old admonition may no longer apply.

First, be a bit skeptical about "testing" articles and videos. The samples are either a) too small to claim to have debunked the "myth", or b) are of so dissimilar of a material that it's not a "test".

Second, understand a lot of the "rules of thumb" that are passed down are simplified versions of what actually caused the rule to be formed in the first place.

Third, often a rule-of-thumb exists because there WAS a reason. That reason may no longer apply.

Example:
Myth: Flintlock ignition is a lot slower than caplock. It is so much slower, a person can hear the difference. Testing was done, and it was discovered that flintlock ignition is only a mere fraction of a second slower than caplock, and the human ear cannot differentiate the difference in the sound of the speed of the ignition. So the myth has been debunked. Was it? The testing used modern made, very well made, flintlock locks, and further in many of the tests used a heated wire to ensure no misfires. The gunpowder was factory made to a modern standard, and had a controlled amount of moisture. Because of the uncertainty as to the amount of sparks generated from each impact of the flint, flint being a natural product and thus unpredictable, the flint was removed.

BUT..., that flint is present in all real-world applications, AND we don't know the quality of the locks used in the past compared to those used in the testing, because of the surviving examples we have so few. ALL that the test proved is, when everything works exactly as intended..., that flintlocks ignite too fast for the human ear to hear a difference compared to the caplock. But just because it worked in a lab, doesn't mean that the "myth" was wrong. IF only 10% of the United States free population owned a flintlock in 1830, that means there were 1,085,697 flintlocks out there contributing to the observable sample at the time when caplocks were coming into common use and the "myth" was formed.



So in the OP's case, first, the reason why such a small gap doesn't cause problems are several.

First, by the time of the scheutzen competitions, the steel is A LOT different than what was used in a hand forged barrel, or the earlier steels when industrialization first began.
Second, that teeny gap isn't actually a gap. See the illustrations below...,



The air gap rule-of-thumb existed before 1880 since by 1880 cartridges were the very common, and this is a muzzle loading rule-of-thumb, right?

So when folks debunked the rule-of-thumb, how many hand forged, welded, iron barrels, or soft steel barrels did they use in their testing? How many different blacksmiths did they contract to make the barrels?

If a mere 10% of the United States population were the gun owners, and only had a single rifle, then 10% of the free population in 1800, at the time of the second US Census, would have been 441,488 rifles with hand forged and welded barrels. That's a pretty big pool of potential problem barrels to claim to have debunked a myth with a handful of barrels as a test sample. Perhaps it wasn't a myth at all? They didn't just make something up for fun.

Oh it was probably quite true, with the gap of a fraction of an inch, or perhaps as much as several inches, there was no problem, but something prompted them to come up with the rule, and instead of something like, "Be sure that in your barrel you have no more than a 3" gap between the powder and ball, unless you have a barrel with a wall thinner than 3/8", whereupon you cannot have a gap of more than 2", and of course if you have an inexpensive barrel made by the Klutz brothers, you cannot have a gap at all"...they went with, "Just make sure the ball is seated against the powder and you will never have a problem like a ringed barrel."

LD

 

[WestKentucky]

I think it’s even simpler than what many here are thinking. As mentioned several times, a huge gap and/or an obstruction are the likely culprits of damage. How do we have this situation in real life? Hurried loading/shooting or poor attention to detail. I take both as the same because who typically has poor attention to detail? Young men who would be hunting. Who fires in such a hurry to short start a ball? Young men on a battlefield. I suspect (and it’s pure conjecture) that a father or military leader didn’t want to risk losing the lives of his boys, and consequently the potential lives of others (starvation or being over-ran) and just flat out told them to never shoot a ball that wasn’t fully seated. If that man became an instructor at a military training camp then it would easily become repeated, and in a time where firearms were extremely expensive and family life relied on them then the importance of never having a failure would be heightened.

Just curious though, in large bores such as cast iron or bronze cannon, is the issue more, less, or similarly dangerous?

 

[Jim Watson]

They don't call them "flinchlocks" for nothing. I found I could flinch a flint TC Patriot clear off the target. A steadier friend could get targets about the same as his .45 ACP.

 

[DocRock]

Because things have changed, and the old admonition may no longer apply.

First, be a bit skeptical about "testing" articles and videos. The samples are either a) too small to claim to have debunked the "myth", or b) are of so dissimilar of a material that it's not a "test".

Second, understand a lot of the "rules of thumb" that are passed down are simplified versions of what actually caused the rule to be formed in the first place.

Third, often a rule-of-thumb exists because there WAS a reason. That reason may no longer apply.

Example:
Myth: Flintlock ignition is a lot slower than caplock. It is so much slower, a person can hear the difference. Testing was done, and it was discovered that flintlock ignition is only a mere fraction of a second slower than caplock, and the human ear cannot differentiate the difference in the sound of the speed of the ignition. So the myth has been debunked. Was it? The testing used modern made, very well made, flintlock locks, and further in many of the tests used a heated wire to ensure no misfires. The gunpowder was factory made to a modern standard, and had a controlled amount of moisture. Because of the uncertainty as to the amount of sparks generated from each impact of the flint, flint being a natural product and thus unpredictable, the flint was removed.

BUT..., that flint is present in all real-world applications, AND we don't know the quality of the locks used in the past compared to those used in the testing, because of the surviving examples we have so few. ALL that the test proved is, when everything works exactly as intended..., that flintlocks ignite too fast for the human ear to hear a difference compared to the caplock. But just because it worked in a lab, doesn't mean that the "myth" was wrong. IF only 10% of the United States free population owned a flintlock in 1830, that means there were 1,085,697 flintlocks out there contributing to the observable sample at the time when caplocks were coming into common use and the "myth" was formed.



So in the OP's case, first, the reason why such a small gap doesn't cause problems are several.

First, by the time of the scheutzen competitions, the steel is A LOT different than what was used in a hand forged barrel, or the earlier steels when industrialization first began.
Second, that teeny gap isn't actually a gap. See the illustrations below...,

View attachment 922731

The air gap rule-of-thumb existed before 1880 since by 1880 cartridges were the very common, and this is a muzzle loading rule-of-thumb, right?

So when folks debunked the rule-of-thumb, how many hand forged, welded, iron barrels, or soft steel barrels did they use in their testing? How many different blacksmiths did they contract to make the barrels?

If a mere 10% of the United States population were the gun owners, and only had a single rifle, then 10% of the free population in 1800, at the time of the second US Census, would have been 441,488 rifles with hand forged and welded barrels. That's a pretty big pool of potential problem barrels to claim to have debunked a myth with a handful of barrels as a test sample. Perhaps it wasn't a myth at all? They didn't just make something up for fun.

Oh it was probably quite true, with the gap of a fraction of an inch, or perhaps as much as several inches, there was no problem, but something prompted them to come up with the rule, and instead of something like, "Be sure that in your barrel you have no more than a 3" gap between the powder and ball, unless you have a barrel with a wall thinner than 3/8", whereupon you cannot have a gap of more than 2", and of course if you have an inexpensive barrel made by the Klutz brothers, you cannot have a gap at all"...they went with, "Just make sure the ball is seated against the powder and you will never have a problem like a ringed barrel."

LD

Lots of good stuff. Thanks. But that image doesn't work for breech seated bullets. There is no loose powder in the case spilling forward to contact the bullet. The powder in the case has some degree of compression and is topped off by a card or fiber wad. There is then a gap between the mouth of the case and the bullet which has been seated/pushed into the bore of the rifle so that it is fully engraved. There is a real and constant gap.

As to steel, this is a practice that began in the 1880s. While the difference between a barrel made in 1875 and 1775 may indeed be significant, we are not talking about modern heat treated steel vs hand forged barrel. My 1871 receiver and barrel were made before the German Proofing Law of 1883.

It certainly appears that air gap in a muzzle loader is a real and serious concern, but also that the conditions applying there are not constant or universal, as in the example of breech seating, the Sharps rifle, or the Fegrusson rifle for that matter.

 

[Loyalist Dave]

No, you miss my point...,
It's a hold over idea from the early days of muzzleloading. It was never corrected as a warning, as the technology progressed, and the warning persists today, even though the fellows found that a tiny gap in lots of different applications does no harm, including breech seating the bullet in front of a full cartridge. As in the original portion of this thread was written, "There are accounts in old timey gun rags of chaps thus seating bullets as much as 3/8" ahead of a case mouth full of black powder, albeit often with a few grains of pistol powder to duplex the load and promote cleaner burning. Roberts, De Haas, Sharpe and others all discuss the process and none of them, nor contemporary gun rags, discuss the terrors of the dreaded air gap." I explained where the "dreaded air gap" came from.


LD

 

[Catman42]

i remember reading years ago that not filling a black powder case full would ring chambers and ruin the gun. i have no reason not to believe what i read. i think that anyone leaving a air gap with black powder or black powder subs. are asking for real trouble and go ahead and do it, it is your gun, not mine.cant under stand why it is being debated?

 

[DocRock]

i remember reading years ago that not filling a black powder case full would ring chambers and ruin the gun. i have no reason not to believe what i read. i think that anyone leaving a air gap with black powder or black powder subs. are asking for real trouble and go ahead and do it, it is your gun, not mine.cant under stand why it is being debated?

Which part of the fact that schuetzen competitors, for example, have been shooting successfully and accurately for 140 years with purposeful air gaps gives you no reason to believe what you read?

 

[Catman42]

your a nay sayer are you not? no futher comment by me, you know it all.

 

[grter]

From whence the myth of the dangerous air gap?

My guess is from anecdotal experience of guns ringing, bulging, and blowing up. They may not have official scientific trials and explicit data to prove it but I would be reluctant to dismiss it as folklore.

I belive there is something to it and do not care to risk ignoring the possible safety hazards that may result if I did.

 

[Flintlock Snob]

Seen more than one muzzle loader barrel ringed by not seating a ball. You will feel the jag get easier to push when you hit the ring. Remember the barrel my not appear "bulged" at all and still be ringed. Its not a safe practice in a front stuffer at all. I have one in my shop ringed by a friend that did not seat.

 

[Catman42]

i would say to the ones who say it is a myth, do and see what happens. my barrel did not bulge but it was ringed. never do that again. also as i stated before a lot of chambers have been ruined by no filling the case full.the reason as i stated before that the oregon rifle barrel company putts a tiny amount of lead in the steel of their muzzleloader barrels is when a customer rings the barrel just above the powder it doesnt blow out and hurt them. the let can cause a bulge but not a blow out. if you dont believe it,do and see what happens. two things you never do. leave a air gap and use smokeless powder in a muzzleloader.

 

[paul harm]

Years back, in the 70s or 80s, there was a magazine called " The Buckskin Report", and in it was a series of articles about guns blowing up 6, 8, or 10" or so from the breech. This was with experienced muzzle loading adults. No one seemed to be able to explain it seeing how they all said they had fully seated the ball. At first some claimed it was the barrels - poor steel. It seems most of them were target shooting and let the guns rest for a bit after loading them. My next door neighbor had just finished a rifle for hunting out west. It had a Bill Large 69 cal rifle barrel. He had just loaded it and his wife called out there was a phone call. He left the shooting bench with the ram rod down the barrel showing a seated ball so when he came back he knew where he was in the loading procedure. When he came back the ramrod was sticking back out the muzzle about 8". He pushes it back down, shoots it and reloads. As he sits there drinking his coffee the ramrod starts coming back up. So he looks at the rifle, the one he built, and there's the hammer down on the nipple. He was compressing the air and that's how we figured the problem with the rifles that blew up in those articles happened. The neighbor was building his own locks and triggers. His triggers weren't double set - the trigger blade rested against the sear, so one had to set the trigger before you could cock the gun. I showed him why he had to change his design so the hammer could rest on half cock with out setting the trigger, and allow the barrel to vent through the nipple. Anyways, yes there is a record of guns blowing up, it's just been too long ago for me to find any reports of it. Just my memory and the problem my friend had with his gun. Oh, John Beard wrote the Buckskin Report, but got sued by Navy Arms for saying their SxS rifle was as not good as originals as Navy Arms claimed. NA said he hurt sales, so John claimed he was bankrupt and shut down the magazine. End of story.