Powder for Longer or Shorter Barrels.

[chorizo]

Finally somebody else with the same information I've been talking about. Black powder has ONE burn rate and only the shape/size of the individual grains control the "burn rate" by surface area exposure.

Thanks @chorizo for this link!

Burn rate can mean different things unless you set parameters on what you are talking about.

The surface area of black powder has one "burn rate" and it doesn't matter if it is ON 1F or 4F if you are talking about the same amount of surface area.

However, 10 grains of 4F has a much faster burn rate than 10 grains of 1F as it has more surface area to burn and can consume (burn) more quickly.

When you talk burn rates, as the surface area burn rate of black powder is constant, it is generally understood that when you compare burn rates you are talking about the same weights of powder in different grinds. (granulations)

 

[Bad Karma]

Went to make a fire in the cook stove in an old line shack. I was pretty young and when I got the kindling going I thought, huh why not just fill the firebox with oak brush kindling instead of going out into the cold for a few pieces of split firewood. Draft open, next thing I know Dad’s roaring “what the heck are you doing boy?!” That stovepipe was glowing red… from a box full of split kindling. Sounded like a small jet engine. Granulation matters.

 

[Uncle Miltie]

The most accurate muzzleloaders ever made had barrels under 30" in length.

And what muzzleloaders would you be refering to?

The heavy barreled target rifles made in the US from 1860-1900. Built to win matches and $$$.

 

[Bad Karma]

The heavy barreled target rifles made in the US from 1860-1900. Built to win matches and $$$.

Yep, still reigning supreme in long range matches.

 

[dave951]

Burn rate can mean different things unless you set parameters on what you are talking about.

The surface area of black powder has one "burn rate" and it doesn't matter if it is ON 1F or 4F if you are talking about the same amount of surface area.

However, 10 grains of 4F has a much faster burn rate than 10 grains of 1F as it has more surface area to burn and can consume (burn) more quickly.

When you talk burn rates, as the surface area burn rate of black powder is constant, it is generally understood that when you compare burn rates you are talking about the same weights of powder in different grinds. (granulations)

And that's exactly my point, black powder has 1 burn rate and the only way to affect it is to expose more surface area BUT that's not changing the burn rate of the powder itself. It still burns at the same rate, surface area exposed to ignition is not changing the actual rate at which it burns. That only means more (or less) is burning at any given instant during ignition. Modern smokeless changes the burn rate by both surface area AND chemical composition hence a much, much wider range.

 

[Nuthatch]

I think if you're looking to optimize the burn rate, then yes, finer granulation for shorter barrel. In general. Other things also affect how much powder burns, such as the internal pressure, which is related to the weight and fit of the projectile. A heavy conical will increase the pressure, igniting the powder faster and will spend a little more time in the barrel before exiting.

But, yes, in handloading for unmentionables, I've used faster powders for shorter barrels and use lighter bullets to keep the pressures down to safe levels. I get faster speeds with less flash.

 

[chorizo]

Black powder does not burn at any higher rate under pressure. It is relatively pressure insensitive. What makes for higher pressure is inertia, as it takes more pressure to get the bullet moving down the barrel the heavier the bullet.

The burning rate of black powder is relatively insensitive to pressure, meaning it will burn quickly and predictably even without confinement.

1. Kosanke, Bonnie J. (2002), "Selected Pyrotechnic Publications of K. L. and B. J. Kosanke: 1998 Through 2000", Journal of Pyrotechnics: 34–45, ISBN 978-1-889526-13-3

https://en.wikipedia.org/wiki/Internal_ballistics#cite_note-12

 

[chorizo]

The following is a nice historical perspective on "heavy loads" Seems like over 110 grains was the norm and 200 grains was not unheard of. With all the whining about recoil when you talk bout using 100 grains of powder you get in this forum, it would seem we have raised a generation of sissies!

Page 313 of Ned Roberts' book

 

[jambuster]

The following is a nice historical perspective on "heavy loads" Seems like over 110 grains was the norm and 200 grains was not unheard of. With all the whining about recoil when you talk bout using 100 grains of powder you get in this forum, it would seem we have raised a generation of sissies!

Page 313 of Ned Roberts' book

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[jambuster]

The following is a nice historical perspective on "heavy loads" Seems like over 110 grains was the norm and 200 grains was not unheard of. With all the whining about recoil when you talk bout using 100 grains of powder you get in this forum, it would seem we have raised a generation of sissies!

Page 313 of Ned Roberts' book

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I use 110 g of Graff fffg behind a .530 ball and .18 pillow ticking patches. (Lyman Plains Rifle). The recoil doesn't seem bad to me.

 

[Rob M.]

My very old gunsmith book-1885- says to use coarse powder in a long barrel, no matter what the caliber. And use fine powder in a short barrel, no matter what the caliber.

Very interesting, thx

 

[Rob M.]

Very interesting post . Funny thing .... I'll find an interesting and thought provoking post such as this and then I'll see one on " Which end of the ramrod do I use " ..... Lordy . Not complaining just .... pondering . Thanks for the info gentlemen .

 

[Grenadier1758]

Sometimes @Rob M., we just have to push back from the keyboard, roll our eyes a few times, take a deep breath and just answer the question while trying to refrain from entering "Use the search engine!".

 

[RIDE-RED350R]

Earlier this week I tried 3F in one of my TCs for the first time. It's a PA Hunter with the 32" 1:66 barrel. I was shooting 80gr by volume of 2F behind a PRB. I tried 70gr by volume of 3F. Accuracy seemed very similar to the 2F loads and were running 1400-1500fps over the chrony. I haven't yet chronied the 2F load. This thread has me wondering if 2F would be best for the longer barreled PA Hunter and maybe try the 3F in my Renegade and Hawken?

I also wonder if there REALLY is powder savings in using 3F as opposed to 2F. Powder measure works in volume rather than actual weight. I'd be curious to weigh the same volumetric charge between 2F and 3F. With 3F being finer, makes me think the same volume of it will weigh more than 2F.

Anyway, I'm going to keep playing around with the 2F and 3F. Looking more for best accuracy, not very concerned about velocity. But I may want a little more than 1400fps with the lightweight by comparison to maxis round ball at about 180gr for a 50cal.

Just alot of thinking out loud on my part here. It's fun playing with different combinations.

 

[Bad Karma]

Earlier this week I tried 3F in one of my TCs for the first time. It's a PA Hunter with the 32" 1:66 barrel. I was shooting 80gr by volume of 2F behind a PRB. I tried 70gr by volume of 3F. Accuracy seemed very similar to the 2F loads and were running 1400-1500fps over the chrony. I haven't yet chronied the 2F load. This thread has me wondering if 2F would be best for the longer barreled PA Hunter and maybe try the 3F in my Renegade and Hawken?

I also wonder if there REALLY is powder savings in using 3F as opposed to 2F. Powder measure works in volume rather than actual weight. I'd be curious to weigh the same volumetric charge between 2F and 3F. With 3F being finer, makes me think the same volume of it will weigh more than 2F.

Anyway, I'm going to keep playing around with the 2F and 3F. Looking more for best accuracy, not very concerned about velocity. But I may want a little more than 1400fps with the lightweight by comparison to maxis round ball at about 180gr for a 50cal.

Just alot of thinking out loud on my part here. It's fun playing with different combinations.

Take a look at this comparison… 80 grains of 2f vs 70 grains of 3f. Looks like 3f is significantly more efficient in your barrel. Now, if it’s as accurate as the 80 grain 2f load you’re in good shape…

 

[RIDE-RED350R]

Take a look at this comparison… 80 grains of 2f vs 70 grains of 3f. Looks like 3f is significantly more efficient in your barrel. Now, if it’s as accurate as the 80 grain 2f load you’re in good shape…

View attachment 260631View attachment 260632

That's really cool! Thank you for sharing

Something interesting though, I got nowhere near the velocity predicted by that calculator. I was in the 1400s.

Does that calculator work in actual charge weight or the volumetric measurement?

I understand different rifles will perform different with the same load. Plus with PRB you have patch material, patch thickness, lube type and whatnot. But that's a pretty significant discrepancy from what is predicted.

I should note that the rifle in question is a flintlock. My first and so far only flint lock. Is there enough pressure lost out the vent hole to account for the much slower velocity I'm getting? Certainly worth consideration I think.

The load does shoot pretty good though. About 2" at 50yds. I know better is very doable. I think I need to try going up from 70gr incrementally and see how groups respond. Accuracy is more important to me than velocity, to a point.

I will stick with 3F. Plan to try it in the Hawken and Renegade too.

Dang it...now I'm itching to go shooting again tomorrow....but I have to rip the front end of my truck apart .


Thank you again for sharing that data

 

[Bad Karma]

That's really cool! Thank you for sharing

Something interesting though, I got nowhere near the velocity predicted by that calculator. I was in the 1400s.

Does that calculator work in actual charge weight or the volumetric measurement?

I understand different rifles will perform different with the same load. Plus with PRB you have patch material, patch thickness, lube type and whatnot. But that's a pretty significant discrepancy from what is predicted.

I should note that the rifle in question is a flintlock. My first and so far only flint lock. Is there enough pressure lost out the vent hole to account for the much slower velocity I'm getting? Certainly worth consideration I think.

The load does shoot pretty good though. About 2" at 50yds. I know better is very doable. I think I need to try going up from 70gr incrementally and see how groups respond. Accuracy is more important to me than velocity, to a point.

I will stick with 3F. Plan to try it in the Hawken and Renegade too.

Dang it...now I'm itching to go shooting again tomorrow....but I have to rip the front end of my truck apart .


Thank you again for sharing that data

Thank @chorizo ! Cool little calculator eh? I would expect some discrepancy. We are talking about any number of variables here after all. The vent, as you mentioned, is one, on and on… wrt the vent size, it seems that many here like a 1/16” vent which is .062” and roughly double what I would allow in a rifle nipple. In fact, at .040 or so it would be blowing the hammers back to full cock, breaking tumblers and what not all. That’s a pretty significant loss of pressure right there. How significant? I surely don’t know.

 

[chorizo]

Thank @chorizo ! Cool little calculator eh?

Really need to thank @Dale Lilly . Early in my Thumper development he provided me with that calculator.

It is a by volume measurement.

I would suspect the tighter a patch on a RB the higher velocity you will achieve as your load will generate more pressure because of resistance.

In short, if more gas is escaping because of a larger vent and there is less resistance because of a looser patch/ball combo, you will not realize the published velocities. The calculator instructions state the following: It is assumed that there is no pressure loss due to the primer hole in muzzle loading guns.

For me, the velocities are right on, but I am using a percussion with a nipple with a .027 hole and an OP wad with a conical. So, with my combination there appears to be minimal pressure loss, so I realize the velocities published.

That is why I say you need to validate what the calculator spits out, either via a chronometer or by the amount of drop at the various ranges.


Here is the webpage for the calculator and instructions:
https://www.p-max.uk/black_powder.htm

 

[Juice Jaws]

I had never thought about this, but it sure makes sen
I have both long and short barrels, but haven't consider the length when loading my horn.

So, the way I understand it:
1. When you want the max push to the ball, it seems you would want the powder to burn completely in the barrel. So, use a faster-burning powder?
2. When you want flame and smoke, you want unburned powder flying out the muzzle and igniting. And use a slower-burning powder?

So, does the grind actually make much of a difference, or is it more a function of the volume of powder used?
What do y'all think?

I think we try very hard to make a simple fun sport into something very hard. I shoot flint locks, smoothbore, rifles, and use 3F for everything, spit patch for everything, run my own ball and shoot the smooth ball with the wrinkle balls and manage to bring home game and ribbons. Plus have lots of simple fun.

 

[chorizo]

I think we try very hard to make a simple fun sport into something very hard. I shoot flint locks, smoothbore, rifles, and use 3F for everything, spit patch for everything, run my own ball and shoot the smooth ball with the wrinkle balls and manage to bring home game and ribbons. Plus have lots of simple fun.

Everybody finds fun in doing different things. What takes the fun out of things is people trying to tell you not to do the things that make it fun for you.

Think about that a bit.