Accuracy via Changing Powder Brand

[Rifleman1776]

At muzzleloaing distances with the sights on most PRB rifles, I don’t think it makes much difference at all. At long distances (in BPCR) it makes a big difference. So unless you are planning to shoot you PRB rifle at or beyond 200 yards you really don’t have anything to worry about.

One other note to those of you that have not had good results with Swiss powder, we’ve learned, it that other sport, that Swiss does not respond well to over-compression. So you might try not ramming the ball as hard against the powder as you do with Goex.

Dan, your super-obsessed bench shooters will disagree with you. Everything in their loading/shooting process must exactly the same shot to shot for them. Anything less than 10's is unacceptable for them.
I'll consider the point about ramming. I am not one to put great pressure on a ball and charge when seating but I'll keep in mind what you said. Worth a try.

 

[Artificer]

My personal experiences with National levels of PRB rifle (Flintlock and Percussion) Competition was at the Primitive Range at Friendship. Even there, the shooters who consistently won the matches were those who spent the most time at working up the very best loads for their rifles to shoot the tiniest groups possible. They also spent the most time practicing shooting and were VERY uniform in their loading techniques considering how they were not allowed a lot of gear that was allowed on "The Tin Tipi Ranges" on the other side of the road at Friendship - opposite the Primitive Range.

My personal experiences with International Levels of PRB rifle (Flintlock and Percussion) Competition was at three International Muzzleloading World Championships. The shooters who won those matches used loading techniques and equipment like "The Tin Tipi Ranges" at Friendship. They were truly interesting to watch when they loaded their rifled guns, whether rifles or pistols.

As I walked the lines as the Team Armourer for two World Championships and watched the shooters loading their rifled guns, it was pretty easy to spot who was going to be in the top two or three Medal positions just by how accurately and technically they loaded their guns. It was also easy to spot who would not make it near the top, due to less exacting loading methods and less exacting ways they shot their rifled guns.

Thanks to my astigmatism, I long ago had to admit I was never going to be a National Level Shooter, though I still spent quite some time on developing the most accurate loads for my rifles. I wanted to make sure it was ME when the scores or shots were poor and not the accuracy of the load in the rifled gun. It also gave me more confidence when hunting with those rifles, though I readily admit it was not necessary to have such an exacting load for that purpose.

Gus

 

[19 16 6]

So, I have always known that the greater part of accuracy is consistency. Velocity also needs to be consistent. Shoot over a chronograph & find out what is happening with velocity.
Therefore if you knew the velocity of the PRB in your most accurate load with powder A, then would it not stand to reason that if you were to duplicate that velocity with powder B, your POI would remain the same ?
O.

 

[Artificer]

So, I have always known that the greater part of accuracy is consistency. Velocity also needs to be consistent. Shoot over a chronograph & find out what is happening with velocity.
Therefore if you knew the velocity of the PRB in your most accurate load with powder A, then would it not stand to reason that if you were to duplicate that velocity with powder B, your POI would remain the same ?
O.

Maybe and maybe not. Chronographs usually only measure speed of the ball after it exits the muzzle. Much would depend on how fast the burn rates of the powders are to get the same velocity, because that would have an impact on how much volume of gas and how fast the volume of gas is built up to drive the ball out at the same velocity at the muzzle. It could/would mean a difference in barrel vibration and that could/would lead to different group sizes.

Gus

 

[longcruise]

I have always thought that velocity is an important element in accuracy. I think that once a sweet spot is found it can be duplicated with other powders by loading to mat h the velocity of the sweet spot. Of course, it goes without saying (then why am I saying it? :haha: ) that consistent loading processes are necessary to keep velocity consistent.

I have absolutely no empirical evidence to support my case. It's purely a gut thing.
I have however personally observed the difference in SD and extreme spreads between consistent procedures and inconsistent ones. They are considerable!

 

[Artificer]

I would add that there are two, rather than one sweet spot of velocity for every powder used. One very light charge and one that is higher in velocity. This is why there are lighter target accuracy loads and heavier long range target or hunting loads.

Gus

 

[Rifleman1776]

Competition was at the Primitive Range at Friendship. Even there, the shooters who consistently won the matches were those who spent the most time at working up the very best loads for their rifles to shoot the tiniest groups possible. They also spent the most time practicing shooting and were VERY uniform in their loading techniques considering how they were not allowed a lot of gear that was allowed on "The Tin Tipi Ranges" on the other side of the road at Friendship

I was always amazed at the scores shot on the Hawken match. It is an aproximate 135 yards, uphill, in a gullie with constantly changing wind and light conditions. Targets turned in were impossible to believe if one was not there observing. Yes, attention to detail and practice, lots and lots of practice, produced those results. It can be done.

 

[Artificer]

Yes, GREAT match to watch. I personally never shot it, though, as I shot flint Northwest Trade Gun Match and Flint Rifle matches.

Gus

 

[Artificer]

I would add that there are two, rather than one sweet spot of velocity for every powder used. One very light charge and one that is higher in velocity. This is why there are lighter target accuracy loads and heavier long range target or hunting loads.

Gus

As a personal example of this, my Douglas Barreled .45 Flint Rifle DEMANDS 42 1/2 grains of FFFg Dupont/GOEX as its target accuracy load. Took me an inordinate amount of time to find that to hit JUST the right sweet spot.

It does not shoot quite that well again until 75 grains of FFFg are used to find the second sweet spot used for hunting. The group is not quite as small as with the light target/accuracy load, but close. However, the groups stay smaller at 100 yards than the light target load.

I have wondered if having two "sweet spots for accuracy" is the source of the somewhat common practice of 18th century riflemen doubling their powder charge for longer range? The lighter target/accuracy load is just the ticket for small game and uses less powder. The heavier load is fine for deer.

Gus

 

[George]

Maybe and maybe not. Chronographs usually only measure speed of the ball after it exits the muzzle. Much would depend on how fast the burn rates of the powders are to get the same velocity, because that would have an impact on how much volume of gas and how fast the volume of gas is built up to drive the ball out at the same velocity at the muzzle. It could/would mean a difference in barrel vibration and that could/would lead to different group sizes.

I believe that the only critical factor is the velocity at exit from the muzzle, and it matters not how it got there. Fast or slow, large volume or small, smooth or rough, none of it matters as long as the velocity ends up the same. And with identical velocities, the trajectories will be the same.

In another thread Zonie told about shooting the same charges of Swiss as he had been shooting of Goex and seeing his gun shoot high. He backed off on the Swiss charge until the groups came back down to where they had been. I think that what he did was match the Goex velocity with Swiss. No chronograph needed, we've been doing it that way time out of mind, but that's what's really happening.

Sweet spots”¦ it has been my experience that I can develop an accurate load at any power level I choose, in any of my rifles. I've always suspected I am doing something wrong, because I've seen hundreds. thousands of posts over the years describing a complete inability to shoot accurately unless that sweet spot is found, and it doesn't seem to work that way for me. I can load 'em up, load 'em down, stop anywhere I want and they shoot just fine. Maybe I wound up with a bad set of guns? :haha:

Spence

 

[Dewey]

I believe that the only critical factor is the velocity at exit from the muzzle, and it matters not how it got there. Fast or slow, large volume or small, smooth or rough, none of it matters as long as the velocity ends up the same. And with identical velocities, the trajectories will be the same.

That sounds reasonable, Spence.

I wonder ... is there a "standard" for granule size? Does 3F from one company equal the same size as 3F from another company? If Swiss "3F" was equal to "3 1/2 F", say, from Goex, that would account for the difference in charge size needed.

It would also mean that when changing powder, you should get the same results once powder granulation size had been accounted for ... or perhaps a bit better or worse if you happened to achieve a better or worse load for your rifle than you had before.

 

[Artificer]

Spence,

Please understand I am not trying to be critical, but what is your definition of accuracy in say a three or five shot group and at what distance?

My concept of accuracy in a regular offhand rifle with PRB is being able to hit a taught stretched string or split the ball on a double bladed axe, virtually every time the shooter does his part at 25 yards. (Oh, and the taught stretched string did not have to be straight up and down. They used to tie strings to branches and anchor them on the ground at angles. Boy, are those hard to hit.) IOW, the rifle is capable of that accuracy IF the shooter does his part. The first time I sat down on frozen ground in a sitting position with a brand new TC .50 cal. Hawken and using their materials, the balls we cast from their mold and their suggested 60 grain powder charge. Temperature was 10 degrees above zero with an estimated 15 MPH cross wind. The three shot group at 100 yards measured no more than 1 3/4" from the two furthest balls in the group. Later, when I tried different powder charges and patch material, I got it down to just over an inch. To me, these are the results of an accurate rifle. Of course I was a LOT younger in those days and when I first fired the Hawken, I had recently gone through two weeks of the most challenging marksmanship training I ever had. :grin:

I have personally seen hundreds of rifles "run across" the super expensive Test Rack at Quantico over the years and got the results of thousands of them having been done. Yes, we did "sneak" in some PRB guns and a couple of Minie' Ball rifles in there as well, though we had to get a bit ingenious to load them without removing them from the rack, which would have negated the validity of the tests.

Even when taking out human error as much as possible when a rifle is locked into the test rack, there is still vertical along with horizontal stringing when there is no wind or outside sources acting on the projectiles (other than the density and pressure of the air, itself) - contrary to what you believe. Over 23 years, there were a lot of other very deeply held beliefs that just did not stand up to this accurate of testing, either.

Gus

 

[longcruise]

The granules between Swiss and Goex are not the same. Not sure about others.

Also, the density varies with different powders. An equal amount by volume may have significantly different weights.

Here is a comparison of a bunch of powders that I compared. All are equal volume.

BP Weight Comparisons done by measuring charges dropped from an RCBS measure at an arbitrary setting.

Graf 3f
55.9
55.5
55.5
55.3
-------
55.55

Goex 2f
51.1
51.7
51.3
51.4
-------
51.37

Goex 3f
52.2
52.1
52.5
52.2
--------
52.25

Elephant 2f
60.2
60.4
60.4
60.1
---------
60.27

Swiss 1.5f
55.9
56.1
56.4
56.2
------
56.15






Swiss 2f
57.4
57.2
57.2
57.4
-------
57.30

Pyrodex RS
37.0
37.1
37.5
36.8
-------
37.10

A "logical" conclusion from the above would be that the denser powders would be more powerful. Not So!

Here are velocity comparisons for most of the same powders above. These were loaded from the same containers as the weight comparisons.

Average velocities for various powders with charges thrown from 50 grain volumetric measure. and shooting a .530 patched ball from a 32" .54 caliber barrel

Graf 3f

1405
1388
1370
1391
1396
Avg 1390


Elephant 2f

1135
1208
1215
1215
1238
Avg 1201


Swiss 2f

1546
1531
1574
1558
Avg 1552


Goex 2f

1349
1362
1376
Avg 1362


Goex 3f

1469
1516
Avg 1492
These two velocities were the only ones obtainable due to bright sun and erratic chrono behaviour

Notice that Elephant was the densest powder but also the slowest powder.

 

[Rifleman1776]

My concept of accuracy

Your concept is yours.
Mine would be one hole groups from rest at no less than 50 yards. The better the gun, the better the results regardless of how held.

 

[George]

Please understand I am not trying to be critical, but what is your definition of accuracy in say a three or five shot group and at what distance?

Oh, there is no simple answer to that, Gus. Accuracy requirements are different for different guns and the jobs I do with them. I work up my best load from a rest, never shoot offhand until I'm satisfied the gun is 'on'. At that stage I'm not interested in the accuracy of the shooter.

For my .30 cal. I'm happy with cloverleaf of 1/2" or so at 25 yards. It's sighted at 25 yards, but I've shot sub-2.5" group at 100 yards with it, and I liked that. With the .40 I can live with a 1" group at 50, like a 3/4" group better. My 20 gauge smoothbore with no rear sight shoots sub-4" groups at 100 yards and that makes me smile.

My point, though, is that with all these guns I can, and have, worked up loads with comparable accuracy over a wide range of charges and distances, sweet spots need not apply. :wink:

Even when taking out human error as much as possible when a rifle is locked into the test rack, there is still vertical along with horizontal stringing when there is no wind or outside sources acting on the projectiles (other than the density and pressure of the air, itself) - contrary to what you believe.

I've never had access to or experience with such testing facilities, so I can only speak as a backyard amateur. If you will read through all my posts in this thread you will see that I never said lateral displacement didn't happen. What I did say was that I don't know of any forces which should cause it to happen, and asked if anyone did know of such. It has never been a problem for me, but there's no guarantee it never will. Until someone can offer an acceptable reason for it, I think I won't be far off the mark if I apply the long-standing precept of western civilization which says that the shooter is guilty until proven innocent. :haha:

Spence

 

[Artificer]

My concept of accuracy

Your concept is yours.
Mine would be one hole groups from rest at no less than 50 yards. The better the gun, the better the results regardless of how held.

I never wrote nor intended my concept of accuracy was anything other than my own. I was giving it as an example in my case only and hoped it would give a starting point to further discussion of what OTHER people consider to be accurate in their rifles. If we don't put some kind of qualifying statement on what each of us consider to be an accurate rifle, then discussion about accuracy can be moot, at best.

BTW, I applaud your concept of accuracy at 50 yards.

Gus

 

[Artificer]

Spence,

Thank you for the detailed reply.

When a rifle is put in a very expensive test rack that holds the rifle rigidly, then vertical dispersion that is in every rifle group (no matter how tiny the dispersion) is not due to the shooter.

I most definitely agree that beyond the vertical (and horizontal) dispersions that each rifle will group without human involvement, then further dispersions (vertically and/or horizontally) is from the shooter. I also agree that most of the dispersion in a group, after an accurate load is found for the rifle, is due to the shooter. I definitely include me as one of those shooters who extremely rarely, if ever, shoot a rifle to its full accuracy potential - even from the prone position.

Gus

 

[Artificer]

VERY interesting information. Thank you.

Gus

 

[Rifleman1776]

discussion about accuracy can be moot, at best.

BTW, I applaud your concept of accuracy at 50 yards.

Such discussion can also be a real :stir:

BTW, that is a concept I have never achieved.

 

[hanshi]

Interesting results, marmotslayer. Another example to support your theory comes from my last powder order (Jack's Battle Powder) manufactured by Goex. I'm a Goex fan and have burned many, many pounds of it. But their JBP was cheaper and I ordered a case of it and split it with a friend.

The first thing I noticed was the velocities from JBP were higher across the board when compared with Goex. It varied from gun to gun and ranged from just a few fps to a considerable increase. Accuracy was also at least as good, so no downside. When weighing my charges JBP weighed less for the same volume than did Goex; yet it gave increased velocities.