AmericanLongRifles Forums
General discussion => Black Powder Shooting => Topic started by: Joe S on September 28, 2014, 09:01:13 PM
-
Two statements that come up from time to time are that a dished breech plug will increase muzzle velocity, and that accuracy decreases as the flash hole size increases above 0.062. I conducted a series of experiments to test these hypotheses by chronographing muzzle velocity.
Dan Phariss supplied the barrel and did all of the necessary machine work. Thank you Dan.
Disclaimer Only one chronograph was injured or killed while collecting these data.
Breech Plug Face Shape Experiment
Experiment Conditions:
38 .50 caliber barrel (Getz)
70 grains Goex FF
Coned flash hole
0.062 flash hole diameter
15 from muzzle to chronograph
Spit lubed 0.018 pillow ticking patch
0.495 Hornady ball
80 90 degrees F
Flat faced breech plug
Breech plug face dished in hemispherical shape with 1/2 ball end mill.
Sample Size 15 for each breech plug
Table 1
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2FTable1.jpg&hash=9691bcd8abc36eaffb88cec57282076165613ac2)
This was the first time I had chronographed black powder loads, so I wasnt sure what to expect. For these data, the standard deviations were 27 and 30 feet/second, and the ranges were 100 and 112 feet/second for the dished breech plug and the flat faced breech plug respectively. Ive seen similar standard deviations and ranges with factory loaded centerfire ammunition, so I feel confident that my loading procedures were reasonably consistent.
The mean muzzle velocity for the dished breech plug and the flat breech plug were 1,609 fps and 1,522 fps, a difference of 87 fps. This difference is statistically significant, that is, the difference in muzzle velocity is real. These results are very robust you can expect to get a statistically significant increase in muzzle velocity in other calibers and with other loads.
A cautionary note: the difference in muzzle velocity of 87 fps we found in this test applies only to this barrel, breech plug shape and load. The exact gain in muzzle velocity you may get with your barrel and load would have to be measured.
This is an easy experiment to do. Lots of folks have chronographs. Should anybody decide to repeat this experiment, Id be very interested in your results.
Velocity as a Function of Flash Hole Size
Experiment Conditions:
38 .50 caliber barrel (Getz)
70 grains Goex FF
Coned flash hole
15 from muzzle to chronograph
Spit lubed 0.018 pillow ticking patch
0.495 Hornady ball
80 90 degrees F
Flat faced breech plug
flash hole diameter (inches):
0.0620
0.0670
0.0730
0.0785
0.0820
0.0890
0.0960
0.0995
Sample Size 5 for each flash hole size
In discussions with Dan about factors that affect accuracy, he has mentioned that bench shooting lore contends that accuracy decreases as flash hole size increases above 0.062. Obviously, the best way to test this is with a machine rest, but I dont happen to have one. However, we can look at two variables that are known to affect accuracy with a chronograph. These variables are average muzzle velocity and variability in muzzle velocity. As a rule of thumb, decreases in muzzle velocity and increases in variability of muzzle velocity will tend to decrease accuracy. So, this experiment was intended to address two questions
1. As flash hole size increases, does muzzle velocity change?
2. As flash hole size increases, does variability in velocity change?
The statistic used to analyze the data for question 1 is called regression analysis. For this type of analysis, we change one variable, in this case flash hole size, and record the effect on muzzle velocity. The data are plotted on a graph, with the flash hole diameter on the X axis and the velocity on the Y axis. Heres the raw data:
Table 2
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2FTable2.jpg&hash=71519036f611797a8232e1f1684d0d9daa0ed3d8)
And heres the graph:
Figure 1
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2FFigure1-1.jpg&hash=d701920419d41fe0f03278bab341612db3e149e3)
Surprise, surprise, surprise as the famous philosopher Gomer Pyle would say. I had expected that as flash hole size increased, velocity would decrease at a linear or perhaps exponential rate. I most certainly did not expect velocity to increase when the flash hole size changed from 0.062 to 0.067.
The first order of business is to look at this unexpected result. What happened? These data were all taken during the same session. Powder, patches and balls were all from a single lot, the same chronograph was used, and the ambient temperature didnt change appreciably during the session, so changes in experiment conditions can be ruled out.
Possibilities include:
1. This is a real phenomenon, and we will see this same result with other barrels and other loads.
2. This is a real phenomenon, but it is a characteristic of this particular barrel and load, and we will not see it in other barrels or with other loads.
3. This is an artifact of random variation in the data, and is not a real phenomenon.
#3 seems unlikely to me, as the data are reasonably consistent; however we have insufficient data to come to a definitive conclusion.
#1 and #2 these seem to be the most likely possibilities, but well have to do a bunch more testing to find out if one of these hypotheses is correct.
Until I can explore this issue a little further, I excluded the 0.062 flash hole date from the analysis. So, heres the graph without those data, and the regression line.
Figure 2
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2FFigure2-1.jpg&hash=b3de886e9b43caeffe12d516bda4463241a15cf8)
Regression analysis gives us two very useful things, an equation for the best line through the data, and a value known as r squared.
r squared is a very useful number, because it tells us how good our model is. The values for r squared range between 0 and 100%, and tells us how much of the variability in y is explained by changes in x. With a value of 0, there is no relationship between the x variable and the measured effect. With a value of 100%, all of the variation in y is explained by changes in x. Obviously, the closer r squared is to 100%, the better the model is and the more we know about the relationship between x and y.
In this case r squared = 54%. That is, 54% of the variation in muzzle velocity is explained by changing the flash hole diameter. The remaining 46% of the variation is known as unexplained error.
I had hoped for a substantially higher r squared value, so I was a little disappointed by this result, although not too surprised. In virtually all of the flintlock data that I have looked there is an unusually high amount of unexplained variability. I dont know why, but this seems to be the nature of black powder and flint ignition.
The regression equation is
Velocity = 1,704 (2,432 x Flash Hole Diameter)
This is handy because now we have a predictive model. If we want to know what the expected velocity is for any given flash hole diameter, we simply perform the calculation. The following table shows the flash hole size, calculated average velocity for each flash hole size, change in velocity from the previous flash hole, and the cumulative change in velocity.
Table 3
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2F3Table.jpg&hash=8a75a0453e44ac82c78483ab2139f5a0bb73e9ef)
As can be seen in the graph and the table, as the flash hole size increases, velocity decreases. Good. This is what we would expect. The data shows though, that velocity doesnt drop off too rapidly. At 0.082, velocity has only dropped off 36 feet/second from the 0.067 flash hole. But by the time we have gone from 0.067 to 0.0995, a total of 79 feet/second has been lost.
Looking at the graph, it appears that variability in velocity is consistent from 0.067 to 0.082 but above 0.082 variability appears to increase substantially. However, with only five samples at each interval, there are too few data to test statistically.
To answer question 2 does muzzle velocity variability increases with flash hole size - I did an additional experiment to get sufficient data to test statically. All experimental parameters are as above, except that 15 shots were measured with 0.0625 and 0.0995 flash holes.
Table 4
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2FTable4.jpg&hash=5553b5693bfea1524564d523865507cc4217798f)
Note that the total range in muzzle velocity was 112 feet/second for the 0.0625 flash hole, compared to 165 feet/second for the 00995 flash hole. The muzzle velocity standard deviation was 30 feet/second for the 0.0625 flash hole, and 48 feet/second for the 0.0995 flash hole. This difference was statistically significant that is, variability in muzzle velocity really does increase as flash hole changes from 0.0625 to 0.0995.
To summarize this set of experiments:
1: Dishing the face of the breech plug will increase velocity. These results are statistically significant and robust. With the experiment parameters used in these experiments, the gain in velocity with a dished breech plug was 87 feet/second. The exact gain that you may get with other caliber and load parameters would need to be measured, and cannot be projected from these data.
2. Between 0.067 and 0.0995, muzzle velocity decreases as flash hole size increases. The velocity difference between these two flash holes was -79 feet/second. It appears that enlarging the flash hole to 0.082 will not have a substantial effect on velocity muzzle velocity loss at 0.082 was only 39 feet/second.
3. Variability in muzzle velocity increases from 0.0625 to 0.0995. The difference in variability with these two flash hole sizes is statistically significant. From the graph, it appears that variability in muzzle velocity between 0.0625 and 0.082 is similar, and that above 0.082 variability starts to increase substantially. There are however, too few data to make a definitive statement except at the extreme flash hole sizes.
4. The decrease in muzzle velocity and increase in variability of muzzle velocity as flash hole size increases support a hypothesis that increasing flash hole size could decrease accuracy.
-
Is it posible to have an increase in presure as your testing went forward if you didnt swab between shots and therefor an increase in velocity?
-
Good question. Ive actually done this experiment before, and found no difference between wiping between shots and not wiping. With a tight patch/ball combination, the barrel is cleaned with each reloading, and there is no fouling buildup.
-
My complements, Joe.
I enjoy reading about this type of inquiry. I like your methods and appreciate the work it took to collect the data. It would be fun to work together.
I could see a next step that tried this work with a barrel with a different bore diameter. I'm curious if either of the tests would show a trend as the bore increases or decreases.
Again, thanks for your work.
"Good science is repeatable"
Regards,
Pletch
-
Really good work, Joe. Thanks a lot.
-
Many thanks for this kind of input! I was reading like crazy looking for the r-square - and there it was! Refreshing to say the least.
J.B.
-
Thanks for compiling this Joe. Very informative!
-
That was quite interesting Joe. Thank you (and Dan) for all the work.
dave
-
Thanks guys. Glad you enjoyed it.
Pletch Im a longtime fan of yours. You have excellent experiment designs and technique and what I appreciate most of all, you always take enough data so that it can be analyzed. Id be happy to work with you in the future on anything. I have a couple of ideas that would be suited to your apparatus. Ill elaborate on this a little more when I have some free time.
I have a bunch of tests I can do with just the chronograph, but they will probably have to wait until next spring. Hunting season is almost here, and besides that, its probably going to take all winter for Dan to make me some more flash holes.
JB I tried to fit the entire data set with a second order equation. No luck. Im not sure what's going on with that 0.062 data. Perhaps you may have some insights. Regardless, Im obviously going to have to explore that problem a little more thoroughly and see what there is to learn.
-
9-29-14
Joe S
Thanks so much for the experimentation and sharing the data.
I have two questions as follows:
1. What is the depth of the 1/2" hemispherical shape in the breech plug?
2. How much was left of the face area of the breech plug face that seals the breech plug to the 50 cal bore?
I hope the two questions are understandable and precise enough for a reply.
Note
I have researched extensively to develop internal ballistic calculations for black powder and a few years ago developed a internal ballistic software program to obtain muzzle velocity. I have come to the conclusion there are too many variables to contend with to obtain consistent and reliable results. The shape of the breech plug face and touch hole size are two examples as demonstrated of the many variables that effect muzzle velocity in developing a reliable internal ballistic software program for black powder muzzle velocity. The chronograph is the most reliable tool for measuring muzzle velocity.
Best Regards,
Robert
-
This is a great experiment, and a Pletch mentioned, should be tried with other bore sizes; and it should be repeatable. Thanks for the effort on this interesting topic.
-
rtadams
I have two questions as follows:
1. What is the depth of the 1/2" hemispherical shape in the breech plug?
As close as I can measure it 0.185 0.190
2. How much was left of the face area of the breech plug face that seals the breech plug to the 50 cal bore?
Not very much. Dan cut it about as far as he could.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2F2HemisphericalBreechPlug.jpg&hash=d47c0df248f840d4329f6dd49e7ea02905246c02)
If anyone else is interested in repeating this experiment, Dan used a standard 5/8 18 bolt to make this breech plug.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi157.photobucket.com%2Falbums%2Ft50%2Fjsharber%2F1BreechPlugBolt.jpg&hash=96bc2f094449680097752d4ca1f43f914a2fbaa5)
-
The 5/8" diameter breech thread limits the depth somewhat. It was done with a 1/2 ball end mill in the lathe.
I tried for as much depth as I could get without the cavity getting too large. In a 3/4 plug they can be deeper. But if the bore is not centered in the barrel then a bore riding center punch must be used to make sure the cup is aligned with the bore.
It did prove Don Kings contention that the cupped breech increased velocity.
Thanks for the work Joe. I love this stuff.
If you email me the report I will transfer it to the newsletter. Knew there was a reason to drag my feet. Need to big a couple of other people for some information too. Some of the tables on this site are too low res to reproduce well.
Dan
-
Can we assume that the flash hole was just in front of the flat faced plug?
-
Some time ago there was a thread on shaped explosive charges that blow their energy directionally through the walls or doors against which they are placed. I think this concave breech plug works on the same principle, which explains its effectiveness in boosting velocity.
-
9-29-14
Joe S
Thanks so much for the experimentation and sharing the data.
I have two questions as follows:
1. What is the depth of the 1/2" hemispherical shape in the breech plug?
2. How much was left of the face area of the breech plug face that seals the breech plug to the 50 cal bore?
I hope the two questions are understandable and precise enough for a reply.
Note
I have researched extensively and a few years ago developed a internal ballistic software program for black powder to obtain muzzle velocity. I have come to the conclusion there are too many variables to contend with to obtain consistent and reliable results. Your experimentation is another example of the many variables that effect muzzle velocity in developing a reliable software program for muzzle velocity for black powder. The shape of the breech plug face as you have demonstrated effects muzzle velocity. The chronograph is the most reliable tool for measuring the muzzle velocity.
Best Regards,
Robert
If everyone used the same lube and the same patch fitment it might be possible to get close calculation. But a slick lube vs a dry lube will change everything. The higher friction lubes, for example should give lower SDs and maybe even higher velocity since the increased friction makes the powder more efficient, this is called "load inertia" in BPCRs where bullet pull and have hard the bullet is set on the rifling can reduce the SD. The condition of the bore is another factor.
As you may know the British experimented with rough reaming shotguns near the breech to increase penetration and also experimented with a rough area near the muzzle to retard the wads to keep them from being blown into the shot charge. In a couple of rifle barrels I had, one was rough/tight at the breech the other not but using the exact breech and ball size etc, the rough/tight at breech barrel was 100fps faster. So there are a HOST of variables in MLs using patched RBs especially that would drive someone to distraction when trying as you did make a program to calculate a velocity.
Dan
-
Some time ago there was a thread on shaped explosive charges that blow their energy directionally through the walls or doors against which they are placed. I think this concave breech plug works on the same principle, which explains its effectiveness in boosting velocity.
I suspect its a similar phenomenon to the shaped charge. But HEs perform differently than BP does. In Joe's experiment the ignition is near the middle of the charge. Experimentation by Elmer Keith and another I cannot recall showed that frontal ignition of a 50 BMG cartridge would cause the gun to be damaged by over pressure. Now I have no idea if it was the frontal ignition or if their attempts were not putting enough impulse on the powder to get good ignition. But they blew up some stuff anyway.
So it could be the shape of the cavity or it could be the point in the charge where its ignited.
Dan
-
Can we assume that the flash hole was just in front of the flat faced plug?
It's about 1/8" in front.
-
Thanks for that Joe. Then if I understand it corectly, the vent was somewhat forward of the dished plug and somewhere into the powder charge instead of at the rear of the charge. Is that right or did I misunderstand?
-
That is correct. Ignition is probably about 1/3 of the way up the powder column from the breech end. Depending on charge volume.
Dan
-
The larger the flash hole the more heat reaches the main charge from the pan ensuring improved ignition and a more efficient burn, with a higher velocity. A fine grain, faster burning, hotter priming powder with a fine grain, high quality main charge can compare with a reduced touch hole. All to do with the efficient ignition of that main charge. That has been my conclusion over the years.
As to a dished face, seems the conclusion here is moving towards the more central ignition of the main charge. Again improving the efficiency of the burn of that charge. The charge surrounds the ignition rather than sitting on top in a column. Makes sense to me.
-
The larger the flash hole the more heat reaches the main charge from the pan ensuring improved ignition and a more efficient burn, with a higher velocity.
This hypothesis is not borne out by the data. Between 0.0670 and 0.0995, velocity decreases with flash hole size.
Velocity increased with flash hole size only between 0.0625 and 0.0670. I think this particular observation needs a lot more research before we can draw any conclusions about it.
As to a dished face, seems the conclusion here is moving towards the more central ignition of the main charge. Again improving the efficiency of the burn of that charge.
This is certainly a testable hypothesis. Maybe Ill add that to my next set of tests.
-
Interesting data. Looking at the increase in surface area, the variability and decrease is less than I would have expected. I can only speculate that the expanding gas from the powder IN the flash hole provides some back pressure to the more central portion of the main charge and that the SHAPE&LENGTH of the flash hole cavity also provides some resistance to flow as well. For example, I would expect a lower decrease in velocity and lower variability with a long straight hole as the diameter changes than an internally coned one, disregarding the difference in ignition speed which would be a practical consideration. I could easily be surprised, too!
Different calibers would be an interesting test as suggested above also, as that changes the "chamber pressure"...
Good work! You won't run out of investigations or variables anytime soon!
-
It would be fairly easy, in a test piece, to make a rear ignition cupped breech.
Dan
-
Interesting fellows - quite interesting.
Should one not strive to find the ball/patch/lube combination that ALWAYS produced the highest velocity per charge BEFORE doing the alterations to breech face and it's effect on speed?
Seems to me a VERY tight combination produced the highest speed for me, over combinations less snug.
I also found a smack of the palm on the starter's knob to ensure the load was down on the powder the same each time needs further testing.
50fps here, 35fps there, 100fps from another technique all adds up to why our loads do not give the same speeds as someone else's loads.
My .40 ran .400" pure lead balls at 2,260fps with a mere 65gr. 3F. That is way higher than anything else I've seen tested and mine were with standard old GOEX 3F. 75gr. of GOEX 2F with the same load, patch and lube ran 10fps slower & exactly the same poi and group size.
The rest of the puzzle - bore .398", ball .400", patch stretchy 100%(crinkle weave) cotton drill (not synthetic) crushed in my mic ran .019"- Goodeoin narrow land, wide groove .010" deep.
-
Couple of observations wrt the cupped breech plug. I can only think of three things the cupped face does (that could be credited for more velocity): moves the ignition point slightly fwd (easy to test), increases the effective length of bbl very slightly, improves combustion chamber shape (it's a hemi! ;D).
And while i have great respect for the work of Keith, I'm thinking that the ignition point change is too subtle and that the "chamber" shape is the underlying cause for performance enhancement. Such that a flat surface would receive all pressure equally, but that a curved surface does not, that it "deflects" (or whatever most appropriate term) the forces somewhat and that the this gives a better push to the ball.
IOW less energy is expended on the curved surface than would be a flat surface--the "bonus" energy pushes harder on the ball.
Those are my internal ballistical thoughts, although it's the effects that count mostest.
(No more flat faces here ;) )
Also, IIRC someone somewhere at sometime made a spring-loaded compression measuring/limiting device to accurately repeat loading compression. I would think such should be employed in this testing for better control of that important variable. cheers and thanks!
-
I can only think of three things the cupped face does (that could be credited for more velocity): moves the ignition point slightly fwd (easy to test), increases the effective length of bbl very slightly, improves combustion chamber shape
We know what the effect of lengthening the barrel is roughly speaking, velocity increases about 10 feet/second/inch. The increase in length with the cupped breech plug was only 0.2 so we can eliminate that hypothesis.
The other two ideas, changing where the powder column is ignited, and the hemi effect are easily testable. All you would need to do is drill three flash holes, one near the breech plug face, one in the middle of the powder column, and one near the forward edge of the column. Plug up the two holes you arent using and start the test.
I hope somebody does this test. I would really like to know the answer, but Im not likely to do it for a couple of reasons:
1. Even if moving the flash hole forward increases muzzle velocity, Im not going to do that on a gun. Aesthetic issues of lock placement outweigh any advantage in velocity that might be gained.
2. Im not sure what Dan would say if I drilled all those holes in his barrel, but its not too hard to guess. Dan lives in a small town in Montana, and as you might expect, the bulk of his vocabulary consists of words that have only four letters.
The question about load compression force is right at the top of my list of experiments to do next. Hunting season and winter are upon us, so as soon as the snow melts out in the spring, Ill get after it. Spring here is July most years, although sometimes it doesnt get here until mid August or so.
-
The question about load compression force is right at the top of my list of experiments to do next. Hunting season and winter are upon us, so as soon as the snow melts out in the spring, Ill get after it. Spring here is July most years, although sometimes it doesnt get here until mid August or so.
Steve Chapman and I did a load compression test using an adjustable collar on the bench rod to produce repeatable levels of compression. Our purpose was to test a theory (not ours) that percussion guns likes compression but flint guns did not.
I'm not sure if it's what you have in mind, but it might.
http://www.blackpowdermag.com/load-compression-and-accuracy/
Regards,
Pletch
-
Pletch
Very interesting.
Do you have the data from the chronograph? I would like to take a look at it if you do. That could give me a lot of insight as to how to conduct another experiment.
What I had in mind was seating the ball with different pressures, and measuring muzzle velocity. The idea is that if muzzle velocity doesnt change across a range of loading pressures, then accuracy is not likely to change either. Conversely, a change in velocity would suggest there may be a change in accuracy. We would want to look at mean velocity and variability in velocity as well.
I like the way you used compression depth rather than a compression force like I had in mind. Force is going to vary depending on patch/ball/lube combination, condition of the barrel etc., but compression depth gives you an absolute repeatable measurement.
As far as an experiment design, I would probably do 5 shots at several intervals and use regression analysis, plus 15-20 shots at the extreme ends to look at variability.
My only critique of your experiment is that 25 yards may be too close to pick up differences in accuracy. Sometimes things that look similar at 25 yards look very different at 100 yards.
-
Joe,
You might want to try Swiss powder in your experiments. When I chronographed a long range rifle using it, the standard deviation was less than 12 fps between shots. This might tighten up the results you are getting with other powders.
-
In BPCR the powder charge needs to be settled to the same level every time its better to add or take away a little powder than to vary the compression. But in a ML unless powder fouling changes the volume this would not be a problem and using a scale to give uniform compression force should work fine in a ML where seating depth is not an issue. Also the compressive pressure available to the ML shooter is a small fraction of that available to the BRCR shooter with a loading press.
If the charge is the same and the compression varies much so will the velocity. If the charge is the same an the density varies so will the velocity since flame spread through the charge is changed and thus the burn rate.
This is why serious slug gun shooters and others use a drop tube in the barrel. A drop tube when the powder is poured through at a consistent and slow rate it will pack the powder to a uniform density in the barrel. This promotes uniform flame spread in the charge and uniform velocities. But even then if the charge is not compressed the same, usually about .030 to .060 is a cartridge the velocity will change. If dropped inconsistently then compressed to the same level as it would be with a compression die in BPCR shooting the Standard Deviation may go from 5-8 fps to 30-40. So if going for minimum velocity variation this is just one of several things to worry about. One other is having a uniform amount of lube and etc etc.
This is of limited importance to the general RB shooter but if trying to reduce variables in testing they must be addressed.
Dan
-
Joe,
We wrote the chronograph reading on the target for each shot we fired. We wanted a record that pared a reading with the shot location. I know I stored the targets for a while, but now I'm not sure where they are. I will try to find them. Also I know I had a crib sheet while we worked. That may be around here.
At the end of the article we listed a few changes we intended to use, because we wanted to redo the experiment. We thought a 50 yard target, Redfield Olympic sights, weighed powder charges and culled balls would eliminate variables. We threw this test together pretty fast.
We were watching compression vs group size when using percussion and flint.
-
I found the targets - 4 flint and 4 percussion - one each for each compression test. Each target has a line drawn from a hole to the chronograph reading. A number also tells the order of the shots within that group.
Private message on the way.
Regards,
Pletch
-
T*O*F
Thanks. Ill see if I can finds some Swiss somewhere. I have a very strong suspicion that a lot of the unexplained variability we see in black powder shooting is due to the powder itself.
-
Right after GOEX started marketing black powder under their own name,the late Tom Dawson tried to use some to regulate both barrels of a double 500 #2 and using his chronograph was able to determine that velocity excursions (variances)made the task impossible.He called GOEX and was told that they were aiming at a market that had no idea what a fine double barreled rifle was and were happy if the gun they had went off.
In other words,the idea of quality control from batch to batch wasn't on the schedule.
We got much better powder later on from GOEX and as far as I know,it is still good powder.The Swiss may or may not be better but the Swiss are noted for high levels of quality control in other things than gunpowders.
Uniform loading techniques with a round ball muzzle loader or long range type is the key to accuracy.The same goes for black powder cartridge rifles used in competition.Ball/bullet weights and compression of the charge will tell the story IF the barrel is any good and crowned properly.
Bob Roller
-
Right after GOEX started marketing black powder under their own name
I think you mean to say marketing Goex powder of their own manufacture. Prior to that, they marketed Curtis and Harvey powder under the Goex brand name.
-
It was DuPont and then GOEX. C&H quit producing when their mill blew up in 1971.
I still have DuPont and C&H.Also a can of 4fg from E.M.Farris's shop in Portsmouth Ohio
and I think it is from King's powder Co.
Bob Roller
-
Right after GOEX started marketing black powder under their own name
I think you mean to say marketing Goex powder of their own manufacture. Prior to that, they marketed Curtis and Harvey powder under the Goex brand name.
Like Bob said:
C&H would not have met the military spec for their contracts. The C&H available here in the 60s and 70s was made in a blasting powder plant in Scotland and was pretty poor stuff, this is why it took a lot of powder to get the same velocity as Dupont-GOI-Goex these three were made at the same plant at Moosic. Dupont never stopped making powder in the US. Largely because the military uses BP in fuses and boosters. Thus the military kept the production alive after Dupont destroyed all the other plants and when there was little call for BP. GOI then bought the plant then it became GOEX after it sold again.
When they finally really blew the Moosic plant up with parts landing in the nearby town they moved to Louisiana.
Dan
-
and further from any town? just wondering