why difference in powder charge?

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desi23

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Grumpy personal gripe & moan: replica percussion Remingtons in .44 caliber are takes on the Model of 1863, not the M.1858.
Yep, all the ones I can find currently made are actually the later model. Years ago there were some made that were closer to the original 1858 model in that they had the covered threads at the breech but they had the cylinder safety notches that appeared later. I had one of them, think it was an ASM. It could have passed for a first model that had been updated with a later cylinder. Curiously it also fouled out quicker than my other Remington replicas. Two cylinders was about all I could get before it became very difficult to cock and I had to pull the cylinder and clean.
 

Whughett

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Yep, all the ones I can find currently made are actually the later model. Years ago there were some made that were closer to the original 1858 model in that they had the covered threads at the breech but they had the cylinder safety notches that appeared later. I had one of them, think it was an ASM. It could have passed for a first model that had been updated with a later cylinder. Curiously it also fouled out quicker than my other Remington replicas. Two cylinders was about all I could get before it became very difficult to cock and I had to pull the cylinder and clean.
So which is entitled to the moniker New Model Army. I just stick to Remington NMA in reference.
 

Spence10

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Here's a straightforward consideration of the question of barrel length and percentage of powder burned from An Essay on Shooting by Wm. Cleator in 1789. He references the Royal Society study and conclusions.
*******************
From the theory we have just given a detail of, it appears that the superior range of long barrels was founded intirely upon the opinion, that the powder fires gradually all the time it is passing through the barrel. The conclusion necessarily drawn from this, was, that the larger the charge, the longer time it was in kindling; and hence, that for any assigned charge, the barrel must be of a proportional length, so that the powder may be completely inflamed just as the ball or shot are about to quit the muzzle: The converse of this proposition was, that in every piece there is a certain charge which will be all fired just at the parting of the ball or shot from the mouth of the piece, and that any addition of powder will not take fire, but will only serve, by its weight, to diminish the action of the rest, and consequently, to retard the velocity of the shot or ball.

If this matter be considered with mathematical rigour, it must certainly be allowed, that, as the fire is not at once applied to every particle of the powder, the whole of the charge cannot be inflamed at the same instant; but it is equally certain, that the progress of the inflammation is so rapid, that the powder is completely kindled before the ball or shot arrives at the mouth of the shortest barrel ever made use of.

To determine this, a number of experiments were made by a committee of the Royal Society, so long ago as the year 1743* and by these it was shewn, that when a barrel was shortened so much that the ball placed before the powder was upon a level with the muzzle, the unfired powder, collected from the discharge, by means of a cloth spread before the piece, weighed but one twelfth of the charge. This was analysed, and found to contain less saltpetre than an equal portion of the same powder did. Hence, and from the extreme minuteness of the particles collected, there was reason to believe, that the grains to which they belonged were less susceptible of inflammation than the rest, owing, perhaps, to some inequality in their mixture: what served in a great measure to prove this, was, that when the charge, and consequently the heat generated during the explosion, was increased, the quantity of unfired powder collected was proportionally smaller. And we may therefore safely conclude, that the powder is completely inflamed before the ball or shot arrives at the mouth of the shortest barrel ever employed. [Italics]

Having now removed the ground upon which the superior range of long barrels was formerly rested, it is necessary that we should endeavour to shew upon what circumstances it does really depend, and to what extent it is found to take place.

The elastic fluid produced by the firing of gunpowder is found, by experiment, to occupy, when cooled to the temperature of the atmosphere, a space 244 times greater than that taken up by the powder from which it was obtained. But from the heat generated during the explosion, this elastic fluid is rarefied to upwards of four times its former bulk. The expansive force of this fluid, therefore, is at the moment of inflammation, one thousand times greater than that of common air, or, which is the same, than the pressure of the atmosphere; or, supposing the powder to have occupied the space of one cubic inch, its expansive force, when fired, is equal to that which would be exerted by one thousand cubic inches of common air compressed into the space of one inch.

As the velocity with which the flame of gunpowder expands when uncompressed, is much greater than that with which the ball, or shot, moves forward, the flame must continue to press upon the ball, and add to its velocity, until it quits the mouth of the piece. This pressure, however, becomes less and less, as the ball proceeds, and ceases entirely when it leaves the muzzle, in consequence of the flame being then allowed to expand itself laterally. Thus, for example, if the charge of powder takes up one inch of the barrel, and the whole length of the barrel be thirty inches, then, when the ball arrives at the muzzle of the piece, the inflamed powder (whose expansive effort is in proportion to the smallness of the space it occupies) extends through thirty times the space it did when the ball began to move, and consequently presses forward with but one thirtieth part the force it possessed at first. Moreover, although the velocity of the bullet is continually increased by this pressure of the inflamed powder, its acceleration becomes less and less as it proceeds through the barrel; for besides that the quantity of the pressure diminishes as the flame expands, the bullet continuing to move faster and faster, must receive continually less and less addition of impulse from the flame pressing behind it. Hence, if two pieces of the fame bore, but of different lengths are charged with the fame quantity of powder, the longer piece will, strictly speaking, communicate the greater velocity and force to its ball, or shot. But as the inflammation of the powder has been shewn to be nearly instantaneous, and as the increase of acceleration which the ball or shot receives after the first impulse of the powder upon it, is not very considerable; it follows that the force with which two barrels of the fame bore, and with the same charge, throw their ball or shot will be nearly the same, unless their lengths be extremely disproportionate.
*Philosoph. Transact. No. 465 p. 172
***********************
Spence
 
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Artificer

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The paper published by the Royal Society itself at the time had a title "Philosophical Transactions". Everything that was published in it is available at Journals | Royal Society with a pretty good search interface.

Unfortunately, despite searching using keyword gunpowder I haven't found any publication around that time (+-50 years) with a title describing such experiment. However I did find one article titled "Experiments to determine the force of fired gunpowder" from 1797. That article is 73 pages so I didn't read it in its entirety (as it was published way after the date in question), but while skimming I noticed on page number 236 the following excerpt.



So this tells us there was a Mr. Robins that published some paper in which he made the above claim prior to 1797. There is a book titled "New principles of gunnery" written by Benjamin Robins(1707-1751). Full text is available in Internet archive. The book is a collection of articles published at various dates including around 1747~1751. The first article is "New principles of gunnery" as read before the Royal Society in 1748.

On page 74 there is proposition 7 and its point 2 is the quote we saw before "That all the powder of the charge is fired,
and converted into an elastic fluid, before the
bullet is sensibly moved from its place"

There is further elaboration of this claim and a description of an experiment on page 80



Further he describes how he measured the muzzle velocities "in 1in barrel" for 1,2 or 3 bullets. No information is given on if the barrel indeed was only 1in or longer barrel was used with results calculated or what the caliber was. Number wise only velocities are given. He notes there was some excess velocity for 2 and 3 bullets, but he claims it can be explained "the flame escaping around the first bullet and acting on the bases of second and third". The extra velocities are around 4% more than expected so not much.

So in modern speak :) the author attempts to establish a given amount of powder will inpart same total energy to a lighter or heavier projectile in a very short barrel. If powder was burning partially a heavier projectile, spending more time in the barrel should have much more muzzle energy than 4% observed.

So there you have it. Is it enough to believe black powder burns completely in the first inch of the barrel? Perhaps.
Here's an original manual that is also not the paper I was referring to, but I think you might enjoy.

New Principles of Gunnery: Containing the Determination of the Force of Gun ... - Benjamin Robins - Google Books

Gus
 

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Here's a straightforward consideration of the question of barrel length and percentage of powder burned from An Essay on Shooting by Wm. Cleator in 1789. He references the Royal Society study and conclusions.
*******************
From the theory we have just given a detail of, it appears that the superior range of long barrels was founded intirely upon the opinion, that the powder fires gradually all the time it is passing through the barrel. The conclusion necessarily drawn from this, was, that the larger the charge, the longer time it was in kindling; and hence, that for any assigned charge, the barrel must be of a proportional length, so that the powder may be completely inflamed just as the ball or shot are about to quit the muzzle: The converse of this proposition was, that in every piece there is a certain charge which will be all fired just at the parting of the ball or shot from the mouth of the piece, and that any addition of powder will not take fire, but will only serve, by its weight, to diminish the action of the rest, and consequently, to retard the velocity of the shot or ball.

If this matter be considered with mathematical rigour, it must certainly be allowed, that, as the fire is not at once applied to every particle of the powder, the whole of the charge cannot be inflamed at the same instant; but it is equally certain, that the progress of the inflammation is so rapid, that the powder is completely kindled before the ball or shot arrives at the mouth of the shortest barrel ever made use of.

To determine this, a number of experiments were made by a committee of the Royal Society, so long ago as the year 1743* and by these it was shewn, that when a barrel was shortened so much that the ball placed before the powder was upon a level with the muzzle, the unfired powder, collected from the discharge, by means of a cloth spread before the piece, weighed but one twelfth of the charge. This was analysed, and found to contain less saltpetre than an equal portion of the same powder did. Hence, and from the extreme minuteness of the particles collected, there was reason to believe, that the grains to which they belonged were less susceptible of inflammation than the rest, owing, perhaps, to some inequality in their mixture: what served in a great measure to prove this, was, that when the charge, and consequently the heat generated during the explosion, was increased, the quantity of unfired powder collected was proportionally smaller. And we may therefore safely conclude, that the powder is completely inflamed before the ball or shot arrives at the mouth of the shortest barrel ever employed. [Italics]

Having now removed the ground upon which the superior range of long barrels was formerly rested, it is necessary that we should endeavour to shew upon what circumstances it does really depend, and to what extent it is found to take place.

The elastic fluid produced by the firing of gunpowder is found, by experiment, to occupy, when cooled to the temperature of the atmosphere, a space 244 times greater than that taken up by the powder from which it was obtained. But from the heat generated during the explosion, this elastic fluid is rarefied to upwards of four times its former bulk. The expansive force of this fluid, therefore, is at the moment of inflammation, one thousand times greater than that of common air, or, which is the same, than the pressure of the atmosphere; or, supposing the powder to have occupied the space of one cubic inch, its expansive force, when fired, is equal to that which would be exerted by one thousand cubic inches of common air compressed into the space of one inch.

As the velocity with which the flame of gunpowder expands when uncompressed, is much greater than that with which the ball, or shot, moves forward, the flame must continue to press upon the ball, and add to its velocity, until it quits the mouth of the piece. This pressure, however, becomes less and less, as the ball proceeds, and ceases entirely when it leaves the muzzle, in consequence of the flame being then allowed to expand itself laterally. Thus, for example, if the charge of powder takes up one inch of the barrel, and the whole length of the barrel be thirty inches, then, when the ball arrives at the muzzle of the piece, the inflamed powder (whose expansive effort is in proportion to the smallness of the space it occupies) extends through thirty times the space it did when the ball began to move, and consequently presses forward with but one thirtieth part the force it possessed at first. Moreover, although the velocity of the bullet is continually increased by this pressure of the inflamed powder, its acceleration becomes less and less as it proceeds through the barrel; for besides that the quantity of the pressure diminishes as the flame expands, the bullet continuing to move faster and faster, must receive continually less and less addition of impulse from the flame pressing behind it. Hence, if two pieces of the fame bore, but of different lengths are charged with the fame quantity of powder, the longer piece will, strictly speaking, communicate the greater velocity and force to its ball, or shot. But as the inflammation of the powder has been shewn to be nearly instantaneous, and as the increase of acceleration which the ball or shot receives after the first impulse of the powder upon it, is not very considerable; it follows that the force with which two barrels of the fame bore, and with the same charge, throw their ball or shot will be nearly the same, unless their lengths be extremely disproportionate.
*Philosoph. Transact. No. 465 p. 172
***********************
Spence
Spence,

Thank you! I believe that is the entire quotation I was referring to, though I must have mixed up the date by 8 years.

Gus
 

Ironoxide

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Pity, authors back then we're not in a habit of quoting the exact title, author, publication date etc.

Perhaps detailed account of the experiment has been included in some book, or was published under a non-obvious title in "Philosophical Transactions", because I've been unable to find it.

Personally I like Mr. Robin's experiment better :)
Here's an original manual that is also not the paper I was referring to, but I think you might enjoy.

New Principles of Gunnery: Containing the Determination of the Force of Gun ... - Benjamin Robins - Google Books

Gus
This is the book (and the experiment) written by "Mr, Robins" I quoted in one of my previous posts (the relevant experiment is described on page 80 of the copy linked to by archive.org). The copy linked to by Gus has that part on page marked 22 (in proposition 7 scholium). Thanks
 
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Artificer

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And we may therefore safely conclude, that the powder is completely inflamed before the ball or shot arrives at the mouth of the shortest barrel ever employed. [Italics]

Spence
During the period of this forum, this theory was proven true in practical application by Henry Deringer and others.

1631891374587.png


"This is the smallest and rarest true “Peanut” size with the shortest barrel length offered by Deringer at 15/16 of an inch with an overall length of 4-1/4 inches. The barrel is rifled for its short length and is of .38 caliber. The barrel has a browned finish without evidence that it was ever treated with the gold colored striping.. This pistol is mounted in German silver and has the “P” proof on the breech without the bordering that usually surrounds this mark. It was probably made between 1855 and 1860. It has been reported that there are fewer than 10 examples existing of this smallest variation known."


DERINGER - AN AMERICAN CLASSIC The pistols of Henry Deringer of Philadelphia, Pennsylvania (collectorsfirearms.com)

Gus
 

desi23

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So which is entitled to the moniker New Model Army. I just stick to Remington NMA in reference.
Technically the 1863 is the New Model Army, the first model was the Remington-Beals model (named after the designer Fordyce Beals. The breech of the barrel was different than later versions and it did not have the safety notches on the cylinder. The second model began a series of changes which led to the third (and final) model and during it's production was generally known as the Remington Army model. After the final modifications (mainly to the hammer and cylinder) the previous versions were usually referred to as the Old Model Army series with New Model applied to the 1863 version.

This is most often of more interest to those collecting original guns as when the reproduction era kicked in the more common 1863 was the version most produced to fulfill the demand. Because of the 1858 Patent date they were sold as the "Remington 1858 NMA) despite actually being copies of the later 1863 version. To most modern shooters the differences are minor and not obvious so of little importance for their enjoyment of the guns. Though, as I stated in my previous comment, at least one company did offer a revolver with the breeching of the earlier model but a later style cylinder with the safety notches.
 

mushka

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I think that I like Gus's printing of the three rules, and his excellent description of pushing or the car to explain increased velocity in a barrel. All that other reading just gave my simple mind a headache.
Thank you Gus.
 

Artificer

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I think that I like Gus's printing of the three rules, and his excellent description of pushing or the car to explain increased velocity in a barrel. All that other reading just gave my simple mind a headache.
Thank you Gus.
The example of pushing a car to help explain increased velocity in a gun barrel came to me back in the 1980's while speaking with the best gun and ammo related mechanical engineers in the country from H.P. White Laboratory.

You are most kind and you are most welcome.

Gus
 

Red Owl

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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
I also have a .50 caliber and settled on 37 gr fffg. Larger charges- recoil an issue and wasted powder.
 

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