why difference in powder charge?

[new2bp]

As happy as I am with my recent dive in and my 1858 revolver, I'm thinking I may end up with a 45 or 50 caliber sidelock percussion pistol. Let my inner pirate out. Aargh!

Anyway, I was perusing what is out there, etc. and got curious about loads (ie, how many shots per pound can I get?) and found this chart in the Traditions manual.

Since it seems the pistols are simply the rifles with a different stock and shorter barrel, I'm somewhat confused on the differences between the pistol min/max loads and the rifle min/max loads for what appears to be the same item, other than wood and barrel length.

Mind you, I'm used to thinking of max loads as a SAAMI spec for a metallic cartridge.... but are the differences here for pressure/safety reasons, or just because with the shorter barrel any more powder is wasted and expended as unneeded extra boom smoke and fire? I understand there will be a minimum needed that will change due to barrel length - gotta have enough go to reach the end without getting stuck. But I'm curious as to why the top end is double for the rifle vs. pistol.

Snip directly from the manual -

 

[Stykbow]

A simple guess is the pistols don’t have enough barrel length to burn that much powder and the recoil factor. I’ve never shot a side hammer pistol, but I’m thinking it be something else to hang on to with a full power rifle load. That’s what my brain is telling me anyhow.

 

[ADK Bigfoot]

I fired one round out of a Lyman Plains pistol in .50 with a 50 grain load of 3F. Snapped the grip off the pistol. Lyman was good enough to replace the stock with a nice note suggesting that I use PISTOL loads in the pistol, not rifle loads.

Good advice.

ADK Bigfoot

 

[TreeMan]

Low powder charges in pistols normally produce the best groups and low recoil. There comes a point in any length barrel of diminishing returns. More recoil and very little added muzzle velocity gained by adding more powder. These are made up numbers so don’t quote me on them. If you have a 50 cal pistol with a eight inch barrel and you get 600fps with 30 grains of powder is it really worth it to load 50 grains of powder for 675 FPS? After that it starts into diminishing returns with the short barrel. You may get 700 FPS with a 70 grain load and 700 FPS with a 100 grain load. There is only so much the powder can do in a short barrel.

 

[hawkeye2]

First disregard all the loads in the instructions that come with any handgun. Most aren't realistic and may have been made up by lawyers. An accurate load for a .44 revolver is 20 to 25 grains of 3f and the max load is whatever you can get in the chamber and still load a ball. A single shot pistol can handle more powder since you aren't bound by having the ball clear the back of the barrel as the cylinder turns but again more powder doesn't always equate to better accuracy and one really shouldn't be trying to kill a bear with one. Quality handgun barrels and the latter revolvers have a much faster twist than a rifle to compensate for the shorter barrel. There is a limit to how much powder can be burned in a given barrel length and the rest will be blown out the muzzle and burn there. Lower pressures and a slower burn rate makes black powder far more forgiving than smokeless. If you listen to the advise given here and don't have anything to prove to the crowd at the range Saturday morning you'll be safe and have an enjoyable time.
I just looked at the chart and see that the maximum load for a .36 caliber rifle is 65 grains of 3f. That's an insane load! You can shoot your .58 with 130 grains of 3f too but I'll bet you'll have a short afternoon at the range.
It sounds like you understand internal ballistics form your experience with smokeless so I would recommend you find a copy of the "Lyman Black Powder Handbook & Loading Manual". I think you would find it interesting and helpful.

 

[ord sgt]

It is estimated that there are 7000 grains of powder in a pound. Divide your load into 7000 and see how many shots per pound you will get.
Me? I use 15 grains FFFg in my Pietta .44. That shoots as accurate as I can hold the revolver.

 

[.36Rooster]

Is it because pistols have a faster rate of twist in the rifling? They'd have to if you think about it, in order to impart the proper spin over the shorter distance (barrel).

I do know that you want to use less powder on faster twist rifles, to keep from stripping the ball out of the rifling, which severely widens groups and decreases the guns accuracy.

I suspect that this is the reason for the difference in pistol charges: You dont want a rifle charge in such a fast twist barrel, because the ball will strip and the gun will not be accurateat that load.

Also, as a manufacturing principle, after taking into consideration the lesser powder charge required for pistol rates of twists, it's likely that pistol barrels are also only proofed at the lower powder charge and hence not rated for more, since it's unnecessary and further cuts manufacturing costs..meaning the company then doesn't have to manufacture it to standards that are unnecessary; and putting that chart in the manual keeps you from suing them if you go above the max load and get hurt attempting a rifle charge through a barrel that wasnt rated for it. You do so at your own risk.

 

[deermanok]

I have 2 sidelock pistols. One is a 45 caliber, the other a 50.
My best load in the 45 is 30 grains of 3f Swiss powder under a patched 440 ball. Very accurate out to 25 yards. I've pushed the load up to 40 grains but lost accuracy and the pistol jumped quite a bit.
With my 50, I've found the best load is 45 grains of 3f Swiss and a 240 grain Hornady PA conical bullet. Excellent accuracy with it.
You might check out Idaho Lewis on modern muzzleloaders. He recently did a quick video, he's shooting a 45 cal. TC Patriot pistol at 100 yards at a steel gong. Pretty awesome stuff.

 

[new2bp]

Thanks all, consensus seems that it is the "will be a waste" factor, a luxury you don't get with metallic cartridges (ever see a 10.5" AR SBR and the fireball it can create?)

Is it because pistols have a faster rate of twist in the rifling? They'd have to if you think about it, in order to impart the proper spin over the shorter distance (barrel).

I would imagine that the barrels for something like the Traditions Kentucky rifle or pistol (one of the things I was looking at that started this all...) are all cut from the same blanks with one rifle barrel and one pistol barrel or perhaps two or three pistol barrels coming from a single blank. Everything else appears identical, except for the stocks. So no, I don't think the pistol version has a different rate of twist.

I do know that you want to use less powder on faster twist rifles, to keep from stripping the ball out of the rifling, which severely widens groups and decreases the guns accuracy.

I suspect that this is the reason for the difference in pistol charges: You dont want a rifle charge in such a fast twist barrel, because the ball will strip and the gun will not be accurateat that load.

Also, as a manufacturing principle, after taking into consideration the lesser powder charge required for pistol rates of twists, it's likely that pistol barrels are also only proofed at the lower powder charge and hence not rated for more, since it's unnecessary and further cuts manufacturing costs..meaning the company then doesn't have to manufacture it to standards that are unnecessary; and putting that chart in the manual keeps you from suing them if you go above the max load and get hurt attempting a rifle charge through a barrel that wasnt rated for it. You do so at your own risk.

Again, I think the mechanics and materials are all the same, so I don't think a different proofing process would be needed, though proofing with hte lesser load in a pistol makes sense for the CYA legal aspect .

Twist to stabilize has a window of optimal rotational velocity, unless you are playing with a gain twist barrel. Basic math function related to the twist rates in rotations per foot of travel and the velocity of the projectile.

 

[megasupermagnum]

Low powder charges in pistols normally produce the best groups and low recoil. There comes a point in any length barrel of diminishing returns. More recoil and very little added muzzle velocity gained by adding more powder. These are made up numbers so don’t quote me on them. If you have a 50 cal pistol with a eight inch barrel and you get 600fps with 30 grains of powder is it really worth it to load 50 grains of powder for 675 FPS? After that it starts into diminishing returns with the short barrel. You may get 700 FPS with a 70 grain load and 700 FPS with a 100 grain load. There is only so much the powder can do in a short barrel.

This is not true, or at least so far exaggerated to be false. You might not be too far off with 30 grains producing 600 fps. At 50 grains, you would likely be north of 1000 fps. At 70 grains, you are probably north of 1200 fps. This is based on actual chronograph testing with a muzzleloading pistol. The exact numbers depend on powder type/grade, loading technique, etc., but the idea that you can more than double powder, and only gain a trivial amount of velocity is not true at all.

 

[.36Rooster]

The lyman plains pistol has a twist rate of 1:30, the plains rifle has a twist rate in the 1:60's. The plains hunter has a twist rate in the 1:40's, i believe. The traditions trapper has a twist of 1:20, and so does the kentucky pistol, while their rifle has 1:66. These pistols are ABSOLUTELY NOT from the same blanks. You can look up the twists for other quality pistols if you wish, but I've seen enough. A pietta navy has a 1:30, for instance. All of them faster rates of twist, shifting the optimal band of accuracy to a lower domain of powder charge. You will strip the balls from the rifling if you go higher.

As for the concept of twist rate and velocity being related (my bachelor's is in mathematics) If you have too much velocity, the rifling cant oppose the torque and it strips due to the fabulous softness of lead, and it does not impart spin like it should (i.e, the difference the between a vector corresponding to the rifling's force imparted on the ball and the ball's torque projected onto a standard unit vector at any point tangent to the ball, comes out negative, imparting slippage by newtons 3rd law, and the ball gives, due to it's softness). Thats how they are related and this is what happens when powder charges are too high.

 

[.36Rooster]

I would not recommend buying any pistol cut from the same blank as a rifle. I would be looking up a more reputable company and pay the extra money for the quality.

 

[Flintlock Whiskey]

A simple guess is the pistols don’t have enough barrel length to burn that much powder and the recoil factor. I’ve never shot a side hammer pistol, but I’m thinking it be something else to hang on to with a full power rifle load. That’s what my brain is telling me anyhow.

When I was kid (about a thousand years ago) I kept increasing my powder charges to the point that unburned powder was falling on the ground, and that was in a .58 Zouave. I think it was something like more than 120gr of 2f. Defiantly has to do with available barrel length to efficiently burn the powder.

 

[Whughett]

It is estimated that there are 7000 grains of powder in a pound. Divide your load into 7000 and see how many shots per pound you will get.
Me? I use 15 grains FFFg in my Pietta .44. That shoots as accurate as I can hold the revolver.

7000 grains in a pound is a true amount as expressed in actual weight. While some shooters do actually weight black powder charges most use a volume measures which may be more or less than weight depending on granulation of the powder.
I haven’t a clue what one pound of black powder would be in grains by volume.

 

[ADK Bigfoot]

7000 grains by weight IS 7000 grains (one pound) by volume. By definition. Any measure that throws a charge of, say 70 grains of Black Powder by weight IS 70 grains by volume. Any other powder thrown from this measure, synthetic or otherwise, regardless of its weight in ounces is 70 grains by VOLUME. It is the Volumetric Equivalent of 70 grains of Black Powder. It's weight may be 55 or 60 grains BY WEIGHT but it is the equivalent of 70 GRAINS BY VOLUME.

ADK Bigfoot

 

[hanshi]

The only pistol I own is a .50 flintlock with an 8" or 9" barrel. I've fired it with 45 grains of 3F at targets and it was very accurate at 25 yards, but it wasn't pleasant to fire. Even with 30 grns it's still a handful but as accurate as a good revolver. Next time I plan to use 20 and 25 grns to see if it gives the accuracy for 25 yard targets. When I take it into the bush as a just-in-case rifle backup it's loaded with 45 grns of 3F.

 

[Mad L]

I am still trying to wrap my brain around "getting an inner Pirate out" with a Percussion pistol??
Must be a river pirate of the 1800s as the GAoP did not have percussions yet.

 

[Ironoxide]

I think it is both a function of the barrel length and tighter twist rates.

I have found my 44 cal remington army revolver likes 24 grains of 3f. It is the amount that is dispensed by my flask's spout so I can load quickly (not for competition use of course). I forgot the exact number for muzzle velocity. I think it was somewhere in the region of 800fps (round ball). Other people swear by using 15 grains and filling the rest of the cylinder with filler to move the ball forward. I do like 15 grains just for plinking .

I also shoot a 58 cal howdah double barrel pistol (by Pedersoli). It has 11in barrels with 1:24 twist. It is most accurate with 50 grains of 3f. Bird's head grip allows one to handle recoil well so more powder can be loaded. The most I tried was 70 grains. There definitely was unburnt powder going out the muzzle with this load.

There are not many guns that make a better light show than an overloaded howda fired when it is getting dark after sunset

Then there is a 44 cal "Kentucky pistol" in flintlock. Barrel length looks like it might be 10~11 in. Most accurate load in it for me is 25 grains. The caliber and load is almost the same as in the revolver, but measured muzzle velocity is 1050fps. About 20% more provided by the barrel being roughly 3 in longer.

I have tried up to 50 grains as the Kentucky pistol has a heavy octagon barrel, but the ball must have been stripping the patch as I couldn't even get it on paper.

So based on this experience I would say for pistols it is generally a good idea to start testing loads that are the same number of grains as half the caliber. With the maximum useful charge being below the number in grains of the caliber.

So for 44 cal you start with 22 grains up to 44 grains. For 58 you start with 28 up to 58 and so on. Mind that all my experience is with 3f powder (not swiss, swiss is 10% stronger allegedly).

 

[Whughett]

I am still trying to wrap my brain around "getting an inner Pirate out" with a Percussion pistol??
Must be a river pirate of the 1800s as the GAoP did not have percussions yet.

During the civil war the confederacy authorized privateers against the Union shipping . Is there a difference between “Privateer and Pirate”?

 

[Artificer]

A simple guess is the pistols don’t have enough barrel length to burn that much powder and the recoil factor. I’ve never shot a side hammer pistol, but I’m thinking it be something else to hang on to with a full power rifle load. That’s what my brain is telling me anyhow.

The recoil factor of a rifle sized powder charge in a side lock pistol IS the Key that too often is overlooked. There would not be that much additional recoil IF the rifle sized powder charge was not burning as much as it would burn inside the pistol length barrel.

I fired one round out of a Lyman Plains pistol in .50 with a 50 grain load of 3F. Snapped the grip off the pistol. Lyman was good enough to replace the stock with a nice note suggesting that I use PISTOL loads in the pistol, not rifle loads.

Good advice.

ADK Bigfoot

Folks, I don't mean to criticize anyone personally, but there are a few times in this thread people have continued an old Myth about how black powder burns in a barrel. That Myth is basically and supposedly that a black powder charge continues to burn in most of, if not the entire length of a barrel. Well, that is just not true and they actually figured that out about 270 years ago, but the Myth continues today.

In 1751, the Royal Society of London conducted tests to see how far down the barrel the powder charge would burn. They found in pistol barrels that it only took One Single Inch of barrel beyond the ball, for the powder charge to burn completely. That's correct, only One Single Inch.

They did notice a few specks of what too many folks then and way too many folks today still believe were unburned "good" powder. HOWEVER, the Royal Society correctly identified those unburned specs as powder that would not have gone off in the barrel - no matter how long the barrel was. Now, why is that?

Even with the barrel of a flintlock having an open hole/vent in the barrel, there has to be SOMETHING in the black powder itself, that will cause it to burn. That means part of the mixture of the black powder has to supply oxygen while the powder is burning and is known in chemistry as an oxidizer. The Saltpeter in the black powder is the oxidizer and provides the oxygen for the black powder to burn inside the barrel. Additional Oxygen cannot get into the barrel from the vent hole once the powder begins burning, because the gas pressure of the burning powder keeps forcing air out of the barrel.

Now even as I write this, I can hear folks disagreeing because of one of two things they have observed or read about, so let's discuss them.

The first bone of contention is a period practice that some folks still do today and that is firing ever larger charges of powder over snow or a large piece of cloth or canvas. Once the powder charge is increased enough, one will notice specks of what looks like good powder on the snow or cloth. In fact, those specks are not good powder at all and are known in Chemistry as "Ejecta." Those specks are one of two things, 1. Already burnt pieces of powder or 2. pieces of powder that didn't have enough Saltpeter to set them off or were covered by burnt material that didn't allow them to burn inside the barrel NO MATTER how long the barrel was or could be.

The second bone of contention is when Muzzle Flash is seen from the side and one see's little sparks inside or just outside the flash. AH-HA!! That must be good unburnt powder specks, right? Nope, what you are seeing there is the Ejecta that is burning ONLY because the super heated gas from the powder hits the Oxygen in the air and raises the temperature of the Ejecta enough to burn it up there, when it would never have burned in the barrel.

The bottom line takeaway from all this is it only takes a few inches near the breech plug for ALL black powder to burn inside a barrel that will ever burn inside a barrel, no matter how long that barrel is.

OK, so MOST of us don't and will never have the super expensive scientific test equipment to prove this, so is there something observable that will prove it? Yes, absolutely.

The observable proof of this is the higher felt recoil in a pistol with rifle size powder charges and what helped cause the Grip of ADK Bigfoot's to snap in two on his Lyman Pistol. IF the rifle powder charge required a much longer length of barrel to burn, then the powder charge would not burn up completely inside the Lyman Pistol Barrel and could not have caused enough recoil from higher gas pressure that helped the grip snap in two. Now I suspect the wood grain of Bigfoot's grip also did not follow the grip, so that made it easier to snap off in two, but it would still not have done so had there not been the gas pressure from the entire rifle powder charge going off inside the barrel.

Gus