Fastest speed you can get with bp


tank mechanic
March 5, 2010, 11:40 PM
What is the fastest speed a bullet can achieve with the use of black powder as a propellant?

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March 5, 2010, 11:44 PM
My understanding is the max is shy of 2,000 fps or so. I believe it was a really big deal when the first smokeless rounds started exceeding that threshold.

March 5, 2010, 11:51 PM
...and we care,why? most don't shoot, say, .45-70 for the velocities we can get. also,with serious calibers,it's not about velocity, so much as retained energy - of which, there is a bunch with a 405 gr. bullet, even at a leisurely 1,000 fps.

tank mechanic
March 5, 2010, 11:53 PM
Thanks for pointing out once again why the highroad sucks BHP FAN. God forbid someone wants to know something that might not be practical.

March 6, 2010, 01:14 AM
I think a .40 with patched round ball can hit 2000 in a long barrel. I know little of the saboted inline stuff, maybe they will hit a tiny bit faster. Dunno why I'd think that....patched round ball has always worked well for me, and the little 40 I had was deadly on mule deer.

March 6, 2010, 01:40 AM
With PRB speeds run from 1200 to at or about the 2k mark. With a .32 1800 fps with a 45 gr prb is about 22 mag but short of a 22 Hornet. A traditional sidelock or flintlock .50 195 gr or.54 225 gr PRB can get 2k with 110 gr of fff 777(Warning: we're all gonna die puttin' that much powder in these old guns). A 30-30 gets 2000 from a 170 gr jfp. A 30-06 gets 2700 from a 165 whatever. That puts the BP guns in 50 and 54 (Probably .45 but I haven't chronoed one) between a 30-30 and a 30-06 for power Not for speed. The hard knock on PRBs is that they fall on their a$$ shortly after 75 yards due to a poor ballistic efficiency. Hence the movement to conicals. After that we re-invent more efficient priming and the 45-70.

The magic of large bore conicals in the 400-700 gr class is that they will shoot at 800 to 1000 yards with the center fires, rainbow trajectory not withstanding.

Lyman and Thompson Center have manuals online if you want to do your own research.

So that's everything that I know about BP speed and ballistics. Take what you want and make smart remarks about the rest.


Tacky remark to be added after my nap.


March 6, 2010, 02:35 AM
Traditions has a sample load chart indicating that a .40 caliber saboted bullet weighing 180 grains can attain a velocity of 2391 feet per second from a .45 caliber muzzle loading rifle with a 150 grain powder charge. But that's probably with a substitute powder.

Ultimate Firearms produces a strong custom inline rifle that will safely shoot 200 grains of powder. Using a magnum rifle primer for ignition, they claim that all of the powder will completely burn in the first 9 inches of the barrel. I'm not sure how fast black powder can push bullets out of their guns but they also claim velocities slightly under 2400 feet per second with 270 - 300 grain bullets. Even if they're loading with Pyrodex pellets, Swiss black powder just might produce similar velocities.

Powder Type Bullet Bullet weight Velocity Accuracy"@100
50 Grs Hornady SST (Target) 300 Grs 1268 fps .250@50 yds
100 Grs Parker Ballistic Xtrm 275 Grs 1876 fps .746
150 Grs Barnes SBT 285 Grs 2153 fps .777
150 Grs Hornady SST 300 Grs 2116 fps .724
200 Grs Powerbelt Platinum 270 Grs 2397 fps .645
200 Grs Parker Ballistic Xtrm 275 Grs 2326 fps .627
200 Grs Barnes SBT 285 Grs 2157 fps .692
200 Grs Hornady SST 300 Grs 2262 fps .636
200 Grs Powerbelt Platinum 338 Grs 2177 fps .726
200 Grs Parker Hydra-Con 440 Grs 2035 fps .814

March 6, 2010, 02:42 AM
Tank, Cosmo had already answered your question,I was merely pointing out what is [to me] a more important consideration,when working within the constaints of black powder.I suppose I could have phrased that better.And....the High Road doesn't suck...after all, you're here.

Jefferson Herb
March 6, 2010, 02:54 AM
It does'nt suck it blows[boom!!!] There are always going to be throwbacks who just want to feel self reliance and will make their own powder ,guns etc.
I don't have a spark model yet,[give me time]but run the gauntlet.After all there are threads from Flint,air to class three stuff;I don't have to like everyones toys but I'm jealous of the ones who have unlimited funds.

March 6, 2010, 04:48 AM
I'm jealous of any toys I don't personally own...

March 6, 2010, 10:40 AM
The theoretical fastest is probably higher than anything you can get from a muzzleloader.

The fastest velocity with smokeless I've heard of in a sorta normal firearm is 6,616 fps. It was a wildcat .30 cal using .50 BMG cases, shooting saboted lightweight steel projectiles (it was a fragment simulator, not a regular gun). But IIRC, the theoretical max is 8,000 or 10,000 fps, which requires a gun with an internally tapering barrel (to keep pressures high) to achieve.

tank mechanic
March 6, 2010, 04:35 PM
Thanks for the interesting replies.

Just to clear the air, I sent BHP Fan an apology PM so hopefully there are no hard feelings.

March 6, 2010, 04:49 PM
It's actually a really interesting question, because one would assume that as a propellant you could keep adding more of it to increase the speed. But there really does seem to be a "wall" when it comes to black powder. As arcticap's chart shows even with more modern BP loadings you are hard pressed to get far into the 2,000's.

From reading about the 19th century African explorers, my understanding is that the inherent limitations of BP forced them to adopt larger and larger bored weapons. Going faster was not an option beyond a point, even with brass cartridges and centerfire primers. So the slugs had to keep getting bigger. That was only changed with nitro powders and after that point in the 1890's the 8 bore, 4 bore, paradox guns and other mega-bores faded from the scene to be replaced with "small" NE doubleguns and high velocity military type rounds.

But I've never heard a scientific explanation for this. It seems you can even fill a bench rifle's barrel with BP and still not get much of a velocity increase.

March 6, 2010, 05:23 PM
Scientific explanation: a bullet can only travel as fast as the propellant gas can, and an expanding gas can move, at the absolute fastest, at the speed of sound inside that gas.

This is also the difference between detonation and deflagration. A detonation means the gas moves at the speed of sound (in the exploding gas, not in air, so blast fronts are generally considered supersonic), while a deflagration means the gas is moving at any speed less than that (but a deflagration can be supersonic in air, too). TNT has a speed of sound of around 22,000 fps, which is why it blows stuff up a lot better than smokeless powder.

So black powder gas has a higher speed of sound than air, but is lower than the speed of sound in smokeless powder gas.

That's also why airguns top out at relatively low velocities (the speed of sound increases with pressure and temperature, so airguns can exceed the speed of sound in regular pressure and temperature air. Especially spring piston ones, since they heat up the air as well as compressing it. Also, Wikipedia says it's independent of pressure, but that's assuming an ideal gas under ideal conditions, which air is not).

Also why the super high-velocity "light gas guns" use light gas. The speed of sound in hydrogen, at atmospheric pressure, is 3.8 times higher than in air.

March 6, 2010, 06:22 PM
No sweat on the apology, Tank, as I kinda deserved it. I wasn't very ''High Road'', so here's me, apologizing right back at you.

March 6, 2010, 06:39 PM
sweet thread!!!! enjoyed this read a lot. :-)

March 7, 2010, 10:25 AM
A fully loaded (110 grains) Great Plains rifle can develop just under 2300 fps.

Loyalist Dave
March 8, 2010, 08:20 PM
the MV of a 16" naval gun is 2657 fps..., it's a black powder propelled projectile..., :what:

well it IS! :D


March 9, 2010, 12:01 AM
From my understanding, it comes down to the mass of the projectile and the relationship between the barrel length and the powder burned. I think the ideal is to burn all the powder before the ball is at the end of the bbl - thus the longer barrels tend to zip it out there a bit better.

I have friends that try to get that long-gong shot via an extra scoop of the black stuff, and mostly it all goes to sparks and fire out the muzzle and onto the ground.

The object is to maximize pressure, minimize projectile mass (for max muzzle velocity). But if you are hunting, you need mass to kill the critter with - which is where the trade comes in. More mass, then slower (but maintains vel with distance better than light). Seems time after time it comes around to the 40 or 45 cal as a great compromise - max velocity with enough mass for deer or antelope. But I know that my 50 will spit them out supersonic - witnessed by the crack and by the chrony...still not enough pill for an elk. There, I go to the slow, large bowling ball style of projectile, using a 60 cal for them critters. but I digress...and could be full of it to (and I am sure I'll be so informed..:D)

Dave A
March 14, 2010, 08:21 PM
Regarding blackpowder and naval guns. Some blackpowder is used in the loading but most of the propellent is smokeless powder. The powder charge consists of multiple silk bags filled with a known weight of propellent. The "back" end of each bag had a red band indicating a layer of blackpowder. This layer was included to insure ignition of every bag in the charge. The guns were brought to level, the breech plug rotated and swung open. The projectile was placed in position on the loading tray and then rammed in to the breech ,then the powder charge was arranged in the tray and rammed slowly in to position behind the projectile. The brech plug is then swung in to position and rotated closed. Then the gun can be fired.

March 16, 2010, 08:43 PM
First, the speed of sound in a given gas is largely a function of temperature, pressure has very little effect.

The technical definition of a high explosive is one in which the flame front propagates faster than the speed of sound in that material. A low explosive is one in which the flame front propagates at less than the speed of sound in that material. There is nothing about the speed of sound itself that says the flame front has to propagate faster or slower. It's not like the effects on a projectile.

The reason for the velocity limitation with BP (or any other propellant) is that the combustion products have to be blown out the barrel and they have weight, so the speed is not unlimited. You can't push a bullet faster than the gas itself can move. Given a BP substitute that has the same energy as BP but weighs less, one would expect a slightly higher bullet velocity with a big charge.

Smokeless powder has a much higher energy content and weighs less, hence higher bullet velocities are possible. Also, note that almost 100% of the smokeless is converted to gas, while with BP you get a lot of potassium salt that is not a gas but a fine solid, (That's what makes the "smoke") so it just adds dead weight and isn't doing anything useful. Not even the BP stink we all love, that's from the sulfur.

March 16, 2010, 09:15 PM
First, the speed of sound in a given gas is largely a function of temperature, pressure has very little effect.

That's only in an ideal gas. I.e., a gas which is trapped in a sealed vessel (in zero gravity), which has been allowed to settle long enough to fill the entire thing to a uniform pressure and temperature.

Any time you've got gases expanding or moving due to pressure differences, you can throw the ideal gas law right out the window. For instance, you'll notice that the free energy of an ideal gas at X temperature and at Y temperature has absolutely nothing to do with the theoretical maximum work that can be obtained from that gas with a heat engine, by cooling it from X to Y.

You'll also notice that precharged airguns completely ignore the ideal gas law, giving muzzle energies in excess of the free energy that the ideal gas law predicts will be in the air tank.

If the ideal gas law were applicable to pressure gradients and gas movements, the ShinSung 707 would never be able to shoot 1250 fps. Yet it does. Precharged airguns get cold when they're fired, which means the speed of sound would decrease, if the air inside there were an ideal gas. It isn't an ideal gas, though, so precharge airguns are free to break the sound barrier if they really want to.

And you're right about the difference between low and high explosives, though. I got confused.

Even so, the pressure front of an explosion, whether low or high order, cannot exceed the speed of sound in the exploding gas.

March 17, 2010, 06:43 PM
You've gone over the top there. I was trying to keep it simple with the point that you can't push a bullet faster than you can get the gas alone to move. Granted, the situation inside the gun barrel is a dynamic one and the temperature and pressure is not the same at all points.

I'm not so sure a pressure wave is limited by the speed of sound, I'll have to go back and look that one up.

BP is an even messier case, since the combustion products are not all gas, some of them are solids. You lose energy pushing them out the barrel.

March 17, 2010, 07:22 PM
then there are the variables...bullet weight? round or conical? saboted projectile? powder granulation? what type of charcoal?

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