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Why does smokeless powder peel open a muzzleloader like a banana?

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I didnt read through everyones comments, so forgive me if redundant.
It boils down to black powder is an ancient formula, essentially unchanged in around five hundred years, and it is remarkably forgiving, relatively low powered, requiring much milder steel (or iron) to contain. Thus the early loooong barrels to ensure adequate combustion.
Modern powders create amazingly high pressures in a fraction the time. Traditional ML firearms barrels would never contain it, and the variances in pressures in modern smokeless powder is great. Just a few grains of popular handgun powders accidentally doubled would blow up the intended handgun. Too little powder and you can get detonation resulting in similar dangeriously high pressure from too little powder.
Volume vs weight....I always laugh at this. Anyone who does a lot of reloading is familiar with the more common smokeless powder measures (mechanical, not digital). They are volumetric. Yes, you coordinate the volume by weight, but basically they are still a volume measuring, but you need to understand the principal behind each.
 
A friend was present on a firing range when a shooter loaded his muzzleloader with a volume charge of smokeless powder. The friend saw the powder container sitting on the bench after the wreck. The man is a reloader and he believes the powder was IMR 3031.

The shooter was gravely injured.


3031 cans are red like goex cans.
 
My BIL is the Coroner in a nearby county here in Southern Illinois. We were talking about muzzleloaders yesterday and he told me about an incident he worked several years ago in his county.

Seems a group of good ol boys were mixing black powder and alcohol one night and firing a civil war era cannon and ran out of black powder. Someone in the group said he had some powder that would work. They loaded the cannon with a load of smokeless powder and touched it off. Cannon was blown to pieces and a couple of guys were killed and several were wounded. Pieces of the cannon were found over a block away. They were packing the powder down with t-shirts.
 
The reason one never shoots smokeless in BP guns is 2 fold.
1. Burn rate...
lay black powder on a paper plate and toss in a match.. and you get a Woooff! and a cloud of smoke. Do the same with smokeless powder and you get a Fizzzelllll. Why is this? Because black powder is a very low order explosive. An explosive that has a very slow burn rate and will only pressure up to a certain point.. and it will maintain that until it burns out. Which is why they make fireworks out of it. If you were to fill the barrel of a modern muzzle loader and hammer in two bullets... then light a fuse in the flash hole... it will spin around and around at a high speed until the powder is consumed. It will not develop enough pressure to rupture the modern barrel.
Smokeless powder on the other hand, is a propellent. A inert compound that has been selected to soak nitroglycerine into. Then its covered with a coating that lets the nitro explode.. at a very diminished rate, depending on the type of powder. The big thing is,,. the more pressure that it develops.. the faster it burns. The pressure spike that it develops can be huge!! The size if the grains, the shape of the grains, the composition of the grains and the coating are how different speeds and pressures are concocted to meet certain criteria. Bullseye pistol powder versus 4831 for example. Bullseye is designed to react very quickly, but there is surprisingly little nitro in it. 4831 on the other hand, has a lot of nitro in it, but its designed by shape/size and coating to build up a LOT of pressure, but at a much slower rate as it has far more nitro in it.
2. Pressure spike.
Black powder will only develop a small amount of pressure, no matter how tightly it is contained. It burns at a pretty slow speed all things considered. When its set on the paper plate.. it goes Wooff!!.. but it will never go beyond a certain pressure and it takes time to burn.
Smokeless powder on the other hand, when burned in a closed container.. the reaction will generate huge pressures in a very short amount of time. The more pressure and the tougher the closed container.. the more pressure it will generate
Black powder burns 560 feet per second for very coarse granulations to 2,070 feet per second for the finer granulations.. Maximum. So the pressure wave is pretty slow. and it will never get any faster and it will not create enough hot case at high pressures. Pressure is self limiting.

Smokeless powder on the other hand.. due to its grain size and shape and how much nitro it has in it ...burns faster and faster as the grains get smaller and smaller
Smokeless powders burn on the order of 13kfps to 21kfps. Thats 13,000 feet per second to 21,000 feet per second and as it burns and the grains get smaller..it burns faster. Hence we have a very HIGH and FAST pressure wave. It can generate 150,000 pounds per square inch doing this.
Old black powder barrels were often Damascus. A long strip of iron was heated red hot and wrapped around a rod and hammered to weld the twist together..more or less. The pressure spike and the speed it hit were low. Which is why a true Damascus shotgun barrel can burst even with a low power AA shotgun shell fired in it. The weld cannot adjust fast enough as that high pressure builds up in a very short amount of time.

Modern muzzle loader barrels are often a low grade of steel and while they may not burst with SMALL smokeless charges fired in it.. that FAST and HIGH pressure wave can fatique the steel, along with any attachment points tied to it and ultimately.. it can split or blow off stocks and hardware with bigger charges.
Yes, in the "good old days" large cartridges such as 8 ga rifles (think Africa) often had a cordite (smokeless) base charge.. a small one.. tiny one.. that was used to ignite the big 1 or 2 oz black powder charge ahead of it. But cordite was a low order explosive slightly faster than BP and it could generate more pressure quicker. "Duplex" loads were a big thing several times in history. And some horrific deaths and injuries came about while using it. So powder manufactures have pretty much stopped using it. A duplex load is again, a faster powder close to the primer and used to set off the main propellent charge. The big problem is... over time, simple vibration will cause those two powders to mix.. and then all sorts of unexpected things can happen. One of which is the bullet making it about 20 feet out of the end of the barrel and falling to the ground in a dust cloud of unburned powder. The other is to over pressure the main charge and blowing out the chamber and launching the barrel down range. Really bad juju.
I would expect any modern muzzle loading barrel to be able to withstand something on the order of a 38 special pressure curve, and not blow up. Maybe even higher. But now we have to worry bout the nipple blowing off, the bolster being launched out the side of the rifle and so on and so forth. All that pressure is being held in by simple small screws and not contained in a tightly sealed cartridge well supported by the cylinder or barrel. And because the high heat that is generated by modern propellents.. we would obviously have flame cutting when directed out a flash hole etc etc.
Best one simply shoots what the gun was designed to shoot. Any smokeless firearm can shoot black powder with no issue except a manure load of smoke and soot. The opposite is NOT true.
At this point.. I suppose I should mention the powder used to make blanks in modern cartridges. That stuff has a goodly quantity of nitro and no retardants. That stuff is on the bleeding edge of high explosives. It burns FAST!!! and with a LOT! of pressure.
I attended the funeral of the son of an aquaintence who had loaded 20 ga shotgun shells properly...but.. his dad had locked up all the gun powder so the now very dead kid had taken 308 military blank ammo, popped the red cap out of the blanks and filled the powder measure with that blank powder. Hey... its gun powder... right? His first shot out of his little Stevens single barreled 20 ga blew up the gun, and blew most of the front of his skull off, along with the front right quarter of his brain. DRT. Dead. Right. There. The forensic surgeon (a fellow shooter) estimated that the primer popped and immediately developed about 200,000 psi in .003 seconds. It was a closed casket funeral.
Addenum:
A single-base powder contains nitrocellulose, whereas a double-base powder contains nitrocellulose and nitroglycerine. Nitroguanidine can also be included as a third energetic base, forming a triple-base propellant
In some cases, nitroglycerine can be replaced by nitroglycol because it is more stable at lower temperatures than nitroglycerine
(I used Nitro in the above paragraphs to simplify things.)
 
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People simply seem to want modern gun performance from a muzzleloader and out of this world performance from a bow. I don’t get it. Folks are shooting non-trad black powder guns and crossbows in what were once primitive deer seasons. This tells me they don’t embrace either hunting with muzzleloaders as our ancestors did or archery as it was practiced until the 1940s. They don’t want the limitations of primitive weapons. Might as well have a single shot deer season where any single shot gun is allowed.

On the topic of smokeless powder in a muzzleloader it’s been covered.
1) the steels that have always been safe for BP are not safe for reasonable loads of smokeless.
2) unlike cartridges which cannot be insanely overloaded because of volume restrictions, a ML barrel will hold a lot of powder.
3) if someone DOES make a ML from 4140 and it is safe for reasonable loads of smokeless powder, those ignorant of the issues will say that Bob uses smokeless in his ML gun, no problems, so I’m gonna use it in mine. THINK OF OTHERS. THINK OF UNINTENDED CONSEQUENCES.
 
The steel in most ML barrels, past and present, is not designed to withstand the pressures common in cartridge guns using smokeless powder. The steel is more than safe for black powder pressures which run 20% to 30% AT MOST of pressures in high velocity cartridge guns. There is no going back since there are tens of thousands or hundreds of thousands of muzzleloaders using steels safe for pressures in the 10,000 to 15,000 psi. 55,000 psi is not uncommon in magnum cartridge guns
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I crossed paths with a video on this forum, can’t remember where, that demonstrated what happens with smokeless powder. Scary! It blew up every ML it was loaded in! I thought it was a bit of an over charge at 150 grains, but with BP I think the barrels would have survived? Is the issue the metal ML’s are made of? Barrel Wall thickness? How can a cheap black gun pop off smokeless forever and an expensive BP barrel becomes a cautionary tale? I don’t want to shoot the stuff, just curious.

150 grains of smokeless?????

Most modern guns of superfabuloso steel would not handle half that of say H110

Muzzleloaders and BPCR guns should never see anything but BP
 
I just saw basically the same topic on another Forum…
Luckily that guy only received 4 stitches in his forward hand..
The plastic toy unmentionable was destroyed by the blast..
 
Original Muzzle loader barrels were made of wrought iron. Modern muzzleloader barrels today are mostly made of low carbon mild steel such as 12L14. The "12" is the type "Carbon Steel - Resulpherized", the "L" means lead has been added, the "14" is .14% carbon. This steel cannot withstand the pressure created by smokeless powder. Modern cartridge barrels are made from much stronger Chromoly steels such as 4140, 4150 and 8620. Here's a list someone recently posted of the steels used to manufacture muzzleloader barrels as of 2012:

Getz - 12L14
Rice - 12L14
Ed Rayle - 8620 or 4150 certified gun barrel steels
Green Mountain - 1137
Charlie Burton (Flintlock Construction, Inc.) - 12L14
Colerain - 12L14
 
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Some black powder target rifles have large diameter barrels which can tolorate huge charges?

And some BP target rifles, like those shot by Fleener, David Minshall, me and a few others - Idaho Louis for instance - shoot comparatively small-bore bullets [yes, that's what they were originally called] of around .45cal, but with charges around 90gr or more. But remember that we are also shooting out to 1200 yards.
 
My BIL is the Coroner in a nearby county here in Southern Illinois. We were talking about muzzleloaders yesterday and he told me about an incident he worked several years ago in his county.

Seems a group of good ol boys were mixing black powder and alcohol one night and firing a civil war era cannon and ran out of black powder. Someone in the group said he had some powder that would work. They loaded the cannon with a load of smokeless powder and touched it off. Cannon was blown to pieces and a couple of guys were killed and several were wounded. Pieces of the cannon were found over a block away. They were packing the powder down with t-shirts.

Can't fix 'stoopid'.
 
30gr of 2400 instead of 30gr of 3Fg - the shooter was injured in the are of the eyes and forehead.

View attachment 178084
in another life i owned a gunshop that catered to LE. the guys would bring me firearms that had been turned in after such a incident. i had a plate rail that ran around the entire shop at the 8 foot height. it was full of remodeled firearms in like condition .
 
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