Barrel wall thickness (Black Powder vs. Smokeless)

Here's a question that I've often pondered but never asked...What's different about the construction of modern cartridge barrels vs. black powder, muzzleloading barrels that allows for thinner wall thicknesses even though the breech pressures are much higher in modern smokeless powder guns? Is this just a modern trend or are the steels which are used different in some way? Even modern inline muzzleloaders have comparatively heavy barrels. I would expect that a modern streamlined and lightweight barrel with the proper rifling could be breeched and used to build a handy and lightweight, fast swinging muzzleloader. So why aren't modern muzzleloaders using this idea?

Razor62 said:

Here's a question that I've often pondered but never asked...What's different about the construction of modern cartridge barrels vs. black powder, muzzleloading barrels that allows for thinner wall thicknesses even though the breech pressures are much higher in modern smokeless powder guns? Is this just a modern trend or are the steels which are used different in some way? Even modern inline muzzleloaders have comparatively heavy barrels. I would expect that a modern streamlined and lightweight barrel with the proper rifling could be breeched and used to build a handy and lightweight, fast swinging muzzleloader. So why aren't modern muzzleloaders using this idea?

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In general modern cartridge rifle barrels are mde out of much better material. But that is not the whole story. I build traditional MLs not guns for fads.
If I want a modern looking, light, short barreled gun I would go down the street and buy one. Probably in 260 Remington.
I don't like most modern guns because the barrels are too light and too short and very difficult to shoot offhand.
I had a nice light 45-70 Marlin. I put on a straight barrel, no taper, 4" longer to make it heavier. Like it a lot more now.
I have a desire to build a 40 caliber flint with a 44 inch "A weight" swamped barrel. I have 2 in the shop right now for another project and really like them.

Dan

Razor62 said:

or are the steels which are used different in some way?

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That's part of it, the other part is actually how the powder burns.
Even fast burning smokeless (nitro) powders have a "burn rate", I mean they burn. Pressure builds gradually to a peak, if you can call a nano second slow.
Black powder is an explosive, it all goes off at once, it "explodes". The pressure is instantanious.
I'm not a good explainer

Hey Razor.
Your thought track my own.
The streamlined barrels were the result of increased understanding in the engineering of guns and the changes in manufacturing techniques. They came together a little over two centuries ago and really took off around the 1861-1865 war.
A 50cal rifled barrel on something approximating a 2/3 scale flintlock musket would probably be nice and handy.

Most muzzleloader rifles are not well designed for snap shots.
The whole process is slow and deliberate.
In most cases you have one (1) shot.....so "Aim little Miss small"
There are many short rifle concept designs to follow, so your choice is quite variable.
If you need a rat-at-tat muzzleloader, build a gatling gun, the original used a muzzleloding cartridge and cap.
The real pleasure of muzzleloading is the slow and deliberate act and lifestyle associated with the pastime.
The technology of the guns today, and the guns of yesterday, are two seperate sciences.
Best regards
Old Ford

CF bbls are made from much higher tensile strength alloyed steels, the bbl threads into the receiver ring so if any expansion occurs at the chamber, the thread fit becomes more engaged and BP produces much lower pressures.{ 50,000+ psi for smokeless vs 15,000 psi for BP}. BP bbls are breeched w/ a male plug surrounded by the bbl so if excessive pressure is created, the bbl expands and loosens the thread fit. Because of the method of manufacture and low tensile strength steels originally used, BP req'd thick walled bbls and this has persisted to this day, although even if the "tougher" modern steels were used for BP bbls, being HC is of utmost importance and a "skinny" bbled MLer just wouldn't "be right"....Fred

Thanks folks. That pretty much answers my question and to be honest supports my hunch as well. For those who assume that I was thinking of building a "modern" muzzleloader, this was not the case. I too appreciate the traditional look, feel and shooting characteristics of traditional muzzleloaders. I was merely curious as to why todays manufacturers don't lean more toward lighter weapons for their biggest market which of course are hunters who are buying muzzleloaders in order to take advantage of the muzzleloading seasons and who are not necessarily interested in sticking with tradition. We've seen polymer stocks, bolt actions, telescopic and fiber optic sights, shotgun primers etc -etc. It just seemed like a logical progression and I was curious if there was some obvious reason why it's not being done that I was overlooking.
I'll keep my traditional smokepoles in either case.

necchi said:

Black powder is an explosive, it all goes off at once, it "explodes". The pressure is instantanious.

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Actually, BP is categorized in the "explosives category" because of its extremely low ignition temperature...not because it explodes...blackpowder does not explode or detonate like dynamite.

Black powder burns like smokeless powders burn...with each granuation size of BP having a different burn rate and a different pressure curve as a result.
ie: 4F is faster than 3F is faster than 2F, etc

It is the different chamber pressures, and burn rates of smokeless vs. Black Powder that determine the kind of steel used in either. We use longer barrels on Mlers in order to burn more powder, to get more velocity. You don't have to do that today with the variety of smokeless powders. To get more velocity, you can just change the smokeless powder you use( within limits of chamber pressures.)

Smokeless powder chamber capacity is controlled by the size and shape of the brass casing. Black powder capacity in a MLer is controlled only by the length of the cylinder or barrel.

Because of the slower way that BP pressure develops, we use a softer type of steel in making the barrels and cylinders for black Powder guns. The steel used is also easier to cut, which keeps the costs down on the final product.

You could use modern steels to make a BP barrel, but it would be more costly to cut the deep grooves needed for a PRB. I suppose you could also leave that modern steel the same thickness as we do with traditional BP barrels. It would simply cost more for the steel barrel. You don't want to use the same steel we use in MLers to chamber some high pressure, high speed modern cartridge. The steel will eventually stretch and fail( often sooner than later).

There are even variations in modern steels used to make various kinds of cartridge barrels. Shotgun barrels normally are made from a "softer" steel than would be used in a high power rifle barrel. Again, steels are matched up with the pressure characteristics of the loads being applied to the steel in use.

roundball said:

Actually, BP is categorized in the "explosives category" because of its extremely low ignition temperature...not because it explodes...blackpowder does not explode or detonate like dynamite.

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I stand corrected Bill Thanks :hatsoff:
I actually do have my head wrapped around the ideas of BP vrs smokless purtty guud, But sometimes I ain't a good explainer :grin:

roundball said:

necchi said:

Black powder is an explosive, it all goes off at once, it "explodes". The pressure is instantanious.

Click to expand...

Actually, BP is categorized in the "explosives category" because of its extremely low ignition temperature...not because it explodes...blackpowder does not explode or detonate like dynamite.

Black powder burns like smokeless powders burn...with each granuation size of BP having a different burn rate and a different pressure curve as a result.
ie: 4F is faster than 3F is faster than 2F, etc

Click to expand...

Blackpowder is classified as a "secondary explosive" - still an explosive but it requires a secondary ignition source. It is most definately an explosive in both the physical and legal sense. It rates a Class 1, Group A hazard stamp in loose powder form. (More hazardous than groups B, C and D)

The brisance is still supersonic and therefore "explosive" as opposed to "fast burning" or a propellant.

Here are some of the burn rates of various explosives.

Explosive designation Detonation speed
Black powder 0.4 km s-1
Ethin/oxygen 2.4 km s-1
Chloratit 3 3.35 km s-1
Lead azide 4.63 km s-1
Gun cotton 6.3 km s-1
Gel dynamite 6.35 km s-1
TNT (trinitrotoluene) 6.7 km s-1 or 7.028 km s-1
7.1 km s-1

Nitroglycerin ~2.5 km s-1 to 7.7 km of the kind of the ignition and the insulation in some cases even up to 9 km s-1

Nitropenta 5 km s-1 to 8.34 km s-1 depending upon load density

RDX (Hexogen) 8.4 km s-1

HMX (Octogen) 9.11 km s-1

CL20 (Hexanitro Isowurtzitan) 9.38 km s-1 or 10.3 km s-1

:grin:
Technical jargon aside, gunpowder burns...dynamite explodes/detonates

Razor62 said:

Thanks folks. That pretty much answers my question and to be honest supports my hunch as well. For those who assume that I was thinking of building a "modern" muzzleloader, this was not the case. I too appreciate the traditional look, feel and shooting characteristics of traditional muzzleloaders. I was merely curious as to why todays manufacturers don't lean more toward lighter weapons for their biggest market which of course are hunters who are buying muzzleloaders in order to take advantage of the muzzleloading seasons and who are not necessarily interested in sticking with tradition. We've seen polymer stocks, bolt actions, telescopic and fiber optic sights, shotgun primers etc -etc. It just seemed like a logical progression and I was curious if there was some obvious reason why it's not being done that I was overlooking.
I'll keep my traditional smokepoles in either case.

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Eventually when the smoke clears and if we are allowed to continue to enjoy this hobby, the round barrels (and the polymer camo stocks and satin plating) will go by the wayside.
The traditional tapered round and octagonal to round barrels will be represented in no more greater numbers than at present.
Profit margins still will rule.

roundball said:

Actually, BP is categorized in the "explosives category" because of its extremely low ignition temperature...not because it explodes...blackpowder does not explode or detonate like dynamite.

Click to expand...

actually, "dynomite" was made out of balck powder until Alfred Nobel invented "nitroglycerine in 1865. if you check the book "Drills and Mills" by will meyerriecks there is a whole chapter dedicated to "explosives" and there composition and uses.

its true bp has a much slower burn rate than modern powders which is why our patched round balls continue to build speed the full lenght of your barrel.

karwelis said:

its true bp has a much slower burn rate than modern powders which is why our patched round balls continue to build speed the full lenght of your barrel.

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Wha

necchi said:

karwelis said:

its true bp has a much slower burn rate than modern powders which is why our patched round balls continue to build speed the full lenght of your barrel.

Click to expand...

Wha

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modern powders go off almost isntantly, bp takes a while. there for the ball continues to accelrate the full length of the barrel

Even so, bullets in modern guns still accelerate as they go down the barrel. As long as there is a force exerting on the bullet, it will accelerate.

It is possible to build a thin barreled modern muzzleloader, if you are willing to pay higher prices for materials and manufacturing. Most of the modern inlines today are made in Spain right next to our traditional guns. The barrels are thick because they can use lower grade steel and still have enough of a safety factor built in.