BP vs smokeless the difference?

[Wingbone]

A buddy asked me the difference between the 2 and I couldnt really explain it. I said they arent interchangable, smokeless burns faster and cleaner, but that was about all I had. Any help with a better explaination? Thanks,
Ken

[arcticap]

I don't know the technicalities, but BP has a basic recipe that makes it all have pretty much the same ingredients & power curve (depending only on granulation), it contains sulpher and is corrosive, and it is considered to be an explosive.
Smokeless powders are made from something like nitrocellulose and they all have different burn rates (and generally much greater pressure curves as you mentioned), and they are not corrosive nor considered an explosive. I think that means that once ignited, they need to be "contained" in order to produce any booming pressure.
It's sort of like the difference between an old fashioned stick of dynamite (black powder) which you can light with a fuse & match and a stick of plastic explosive which requires a blasting cap to ignite. A higher ignition temperature is required I guess.
You just couldn't use smokeless powder to ignite a flintlock, and those model rocket engines use a form of black powder. Since it's a slower burning pressure curve, it provides a slightly more gentle acceleration to a model rocket. Whereas smokeless powder might blow it up because it burns up/explodes too quickly! Fireworks are also a form of black powder with all of the spectacular aerial displays, etc...potent but not too potent, grain for grain.

[Maser]

Actually smokeless powder burns much slower than blackpowder and that's why black powder has so much smoke to it. All that smoke is unburned powder that didn't get oxydized the right way because it burned so fast and the bullet left the barrel before it could finish burning. That's why smokeless powder has higher pressures is because it burns slower and almost completly oxydizes all the way.

Here is an easy way to explain the difference. Smokeless powder burns. Black powder explodes.

[gmatov]

Smokeless powder also " explodes", just at a lower rate, depending on the "blend".

BP actually "burns" at a given rate, I don't know, offhand what it is, maybe 25,000 feet per second.

GENERALLY, it will produce something in the range of 10 to 15,000 psi. It CAN however go to well over a 100,000 psi.

Smokeless powders are pretty potent, too. It is mandatory that you follow reloading data to load ammo. You may load as much as 20 grs of Unique or 2400 in a 44 mag case 9 grs or so of Red Dot in the same case, same gun, and get at least as high velocity, more kick, from the faster burn, almost an "explosion", and uncomforably high pressures.

The powders that produce the highest velocities and the lowest pressures are progressive burning powders, they don't "detonate" in the chamber or the case, they continue burning and building pressure all the way up the barrel.

A short barrel will blow out unburned smokeless powder, too.

Smoke is not unburned BP, it is water vapor from the Potassium Nitrate.

Sulfur is not the corrosive, it is the Chlorates left in the Potassium Nitrate when it is made into BP. Purer KNO3 has less Chloride in it, makes for a less corrosive BP.

BP is not bad, depending on whose it is.

A 100 years ago or more, the "cowboys" fired their BPs and rinsed them in the "crick". They either dried from the heat of the sun or they greased them with the bacon grease from breakfast, lunch and dinner. They ate a lotta fatty foods and don't seem to have died from all that many heart attacks.

Cheers,

George

[Steve499]

They didn't NEED heart attacks, George. They had bullets, arrows, stampedes and saloon brawls!

Steve

[Wingbone]

Thanks for all the help guys.

[Maser]

Another thing to take in condiseration is the powder's grandulation size. The finer the powder is the more powerful it will be.

[gmatov]

Got me , Steve. Then, too, stove up old cowpunchers might have lived as long as the gout ridden rich folk who DID live to a ripe old age..

2f instead of 3f is not a big boost, There is no longer a "cartridge powder", the coarse stuff used to load the .44 and .45 cartridges, that was 1f, and they found they had to reduce the charge to shoot in cartridge revolvers.

There is STILL a barrel/cylinder gap in cartridge revolvers. Why so much more KICK, which is what the buyers complained of? Were the frontiersmen simply wimps?

Today, shooters of 44 Mags want 300 gr bullets at 1500 fps. Ridiculous!

Cheers,
George

[Whisk]

BP=carbon based (BP is charcoal, sulphur) substitutes use other carbon based (Triple 7 is sucrose or sugar based for example) while smokeless are petroleum distillate (nitro soaked cellulose) based.

Smokeless burns slower creating more ultimate pressure. Actually Triple 7, et al are more "modern" than smokeless powders!

[FLATWOODS FRED]

Wingbone,

Comparing smokeless to black powder is like comparing apples and oranges.

First black powder is a mechanical mixture were as smokeless (nitro) powders are a chemical compound.

Black powder (real black powder) is composed of potassium nitrate, sulfer and of course charcoal. The exact ratios vary from manufaturer to manufacturer and its intended use. As for burn rates it can vary greatly depending upon the mix ratio and the type and quality of the components. Not just the grain size. For instance GOEX uses hardwood (maple) charcoal. Back in the day hardwood was considered a very poor charcoal to use in black powder (slow burn). The best you could hope for was a musket or low grade rifle powder.

The charcoal of choice for high grade rifle or sporting powder (fast burning) was Alder, more specificly Buck Thorn Alder as used by the Swiss today. How the charcoal was processed makes a big diffrence too in regards to wether the powder will be moist burning. The finish and glazing has a lot to do with it as well. GOEX uses lots og graphite. Graphite hinders the burn. The only advantage is it prevents the powder from clumping in the can. Not a big deal. A few shakes and its ready to go.

As for corrosivness; black powder when burned creates by products, mainly potassium carbonate (potash) and potassium sulfate. Potassium carbonate readily absorbs moisture when the relative humidity reaches 30% or greater. In fact, at 80% its almost a liquid. Thats why cleaning with nice hot water works so well.

Anyway, ONLY at 30% humidity can the potassium carbonate form galvanic corrosion cells which can cause pitting. If the humidity is lower, the potassium carbonate is too dry. If it rises above 30% the potassium carbonate quickly becomes too wet for the galvanic cells to form. In reality the conditions which can lead to galvanic action are so narrow that its really a non-issue.

However, what is an issue is the fact that todays potassium nitrate is formed from potassium chloride. If it is not 99.9% pure then the remaining traces of potassium chloride WILL cause pitting. This is only a worry if you are shooting cheap powders. Flushing the bore with hot water will nutralize any potassium chloride.

If you think your BP sub is non-corrosive think again. Many leave nasty percholates behind.

Now lets look at nitro powders:
Nitro powders are chemical compond created by exposing celulouse material (wood, cotton, plant fiber etc.) to nitric acid plus adding a variety of modifiers. Yes, laid out in a string they burn much slower then black powder. However, once confined they burn MUCH, MUCH Faster and generate much higher pressures.

A lot of folks have made the mistake of looking at modern shotshells with thier dram equivelant and figure "oh... 3 dram that will duplicate a 3 dram black powder load" At the very least a fine shotgun my be ruined. Again, the pressure, pressure curve and duration is simply not the same.

Incidenty,

The more "kick" BP seems to give is a result of all the solid residue. Nearly 55% of the charge remains as solid particles of fouling that is forced up the bore. Most of which is ejected out the barrel. Its akin to adding more shot or using a heavier bullet.

[Steve499]

Good post, Fred! Welcome to TFL.

Steve

[FLATWOODS FRED]

Just a few more thoughts. Never use the word "DETONATE" when discussing powders. A compound or substance that detonates is unpredictable and un-wanted in the powder and explosives world and is a real no no.

The proper term is deflagulation. In otherwords it surface burns from the outside in. If a powder or explosive detonates that means it can be set-off by a pressure wave traveling through it. In the explosives industry they use a fall hammer test to determine just such sensativity. BP has a moderatly low sensitivity. Propellents the detonate are to be avoided at all cost.

Anyway, another big diffrence between black powder and smokeless is how they are best ignited. Black powder is ignited by heating particles to incandencense were as smokeless is best ignited by heated vapor. What does this mean? Back in the old days there were indeed primers meant for black powder and those meant for smokeless. In order to heat the particles to incandecent you need a long enduring hot flame - thats why todays magnum primers work well.

As for pressure; BP can produce termendous pressures if given the chance. W.W. Greener mentions in his fine book "The Gun and its Development" a 450 BP Express rifle that burst. It seems the owner used a cheap fine grained BP that was heavily compressed. The 450 like the 45-70 etc. is a tappered case. In effect the powder ignited at the primer and of course started the whole load column in front of it moving. However, that tapered case caused the un-burned powder to basicly form a wedge. With no place to go the breech let go. This is the same reason why the original 303 British, loaded with a heavily compressed charge of BP and todays modern BP sub pellets have a hole in the center.

Another contributing factor was the "Cheap BP" many low quality powders are improperly glazed. As the powder grains dry a thin hard coating of Potassium nitrate forms on the surface. If left to dry on its own it becomes dull and dusty. However, during the polishing process the grains rub together with a substantial amount of pressure which polishes and hardens this film. Properly polished the powder will indeed look and shine like little black diamonds. The grains will actually "snap" when broken. poorly glazed powder will simply crumble. No-doubt the powder used in that 450 BP Express rifle did exactly that. In other words, under compression he probably ended up with a case full of very, very fine particles and dust. Which would have raised pressures on its own.

Well I have rambled on enough. Time to get some work done.

[gmatov]

Fred,I think I have read that the problem with "proof tested Nitro-cellulose barrells" was that higher temps created higher pressures.

They came up with "Safari Grade" ammunition, for those instances when the Hunter was hunting Africa, with high temps.

Pressures rose astronimacally. Blew up guns. Would be a great surprise to see your barrell splt like a banana skin when shooting at a charging lion. They ain't [color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color][color=#FF0000]█[/color] cats, are they?

Oh, as to the W.W.Greener book, it is that one that seems to find that desert heat caused BP AND Cordite to cause substantially higher pressures, sufficient to cause blowups of multi thousand dollar double rifles.

I wish I couuld DL that one. I don't really want to buy it, though it would provide ammunition for sites such as this, which has so MANY doubters of ANYTHING that is not in their aura of belief.

Cheers,

George

[FLATWOODS FRED]

GMTOV,

To some degree yes. The early nitro powders were indeed suceptable to pressure variations due to heat. In fact, its still a bit of an issue today. The 458 Win. Mag. is a prime example. Early factory ammo gave very erratic performance due to temp variations. It was actually down loaded to compensate. It sort of gave it a bad name among some big game hunters.

As for proof. Every English barrel was given three levels: Provisional proof, Definitive proof and Service charge. Service charge is the important one. It is the do not exceed number. One problem with old nitro proof barrels is the type of nitro based powder used back in the day. For instance, for quite sometime the English proofed thier shotgun barrels using Schultze Powder (nitrated wood fiber). This was an early bulk smokeless (some call it semi-smokeless) much like Duponts Lesmoke. It was infact the first commercally available smokeless powder in 1868 there abouts. There are no powders on the market today that duplicate it. It came in several sizes, the orginal being a 42 grain powder, "Imperial" 33 grain powder and "Cube" which was a 30grain powder which was considered standard for a 12 bore load. Not like handloading today with all its combinations!

Before the advent of true nitro powders (colloided nitrocellulous) between 1890-1895, there were a whole host of powders such as this. Schultze powder lasted into the 1920's.

So..... if that old English gun is proofed for nitro beware - not all nitro powders are cut from the same cloth.

[MacGille]

Black powder is classified by the Federal government as a class A explosive. It can be detonated by heat, or pressure. It can even detonate with an electric charge. (it would have to be huge) Smokeless powder on the other hand is classed as a Flammable Solid and requires an ignition source of incandescent vapor to ignite. Smokeless will produce super high pressures under confinement and will burn very rapidly under the right circumstances. Black powder burns extremely fast under any circumstance, even unconfined. The major difference is the gases each produces. BP is a dirty powder, it leaves a lot of the mass as fouling and visible gases (vapors). pressures start out high with BP and it truly explodes in the chamber. Smokeless Burns slower initially and the burn rate accelerates with pressure. It produces an invisible gas that is very hot and expands rapidly. These gases can cause erosion in the throat that is worse than the corrosion of BP. Smokeless is made of nitro-glycerin and nitro- cellulose (double base powder) and commonly has other additives that control burn rate and gas production. The shape of the grains has a lot to do with its burn rate and compression as a rule is not a good idea with smokless. That being said, there are compressed loads in some calibers. There is a lot of information on both of these propellants available to the shooter, check with the powder manufacturers for books on these. The main thing to remember is, KEEP THEM SEPARATED FROM EACH OTHER, AND NEVER MIX THEM. Always treat black powder like you would a poisonous snake. Be cautious with it, and a little scared of it. You won't like it's bite.

[FirstFreedom]

1. In the presence of oxygen, black powder is more dangerous than smokeless - it burns at the same rate whether oxygen is present or not. Ver fast. Smokeless powder burns much cooler/slower in the presence of oxygen (out of the case). On the other hand, when confined inside a case without oxygen, nitrocellulose (smokeless powder) greatly magnifies its burn rate and temperature, creating much higher pressures and thus makes a bigger more powerful explosion than black powder. Thus allowing you to propel bullets faster with the same amount of powder. But have a bigger, more powerful explosion means you must have a stronger-built receiver and chamber to contain the pressures.

2. Black powder gives off a LOT of smoke/dust/particles, and leaves more corrosive residue/fouling. Smokeless powders give off very little smoke/dust/particles and leaves far less residue/fouling - hence the name "smokeless".

3. They are different molecular compositions.

[FLATWOODS FRED]

Black powder gives off a LOT of smoke/dust/particles, and leaves more corrosive residue/fouling.

Close to 55% of the original black powder charge remains as solids (Potassium carbonate & potassium sulfate) A good portion of that is ejected out the barrel. Its all this solid matter being pushed up the bore that gives BP that extra bit of recoil as well. Its like adding an extra shot or a heavier bullet to your smokeless loads.

One mistake folks make in the BP/Smokeless comparison is believing that because the barrel gets hot real fast shooting BP that it burns hotter. It does not. BP unconfined burns real fast. (I use to know the actual numbers) while smokeless burns real slow. The reverse is true when they are confined inside a cartridge. Smokeless (and it varies from powder to powder) produces a very sharp pressure curve - most of the action taking place in the breech) BP is more horseshoe shaped. It burns for a far longer duration. Its this that causes a BP barrel to warm up so quickly.

BP may not produce the extreme tempreture of smokeless but the far longer duration exposes the barrel to what heat it does generate for a much longer duration. Its akin to passing your finger through the flame of a lighted candle. Do it quickly and you feel nothing. Do it slowly and OUCH!

As for oxygen thats what the potassium nitrate contributes to the mix.