Funny this topic came up because I had the exact same thoughts yesterday. I picked up a new 642 and started looking at the charts for faster powders that might be good with a short barrel. I was surprised to see some posted charts had true blue listed pretty high up, faster than 231.
Burn rate charts
- Thread starter AJC1
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Steamboat Springs Airport/Bob Adams Field (beautiful)
- But . . .
Typical commercial runway length is between 8,000 feet and 13,000 feet.
Bob Adams' is barely 4,400 feet -- and you're starting w/ ~7,000-ft altitude. . .
... thin air and mountains everywhere.
Parallel that w/ unpublished load development w/o instruments for either
probable pressure on one end, or resultant velocity on the other...
...really bad juju
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rfwobbly
Member
Statements like this ASSUME that ALL available load data is published on the web. That is false. That is 'Google knows everything' type thinking. Powder companies release only a fraction of their load data.
- True, some of that data simply proves a powder is not useful for a certain load. Say W231 used in 9mm with 147gr. Testing may prove a slower powder does a better job for general reloading, but they still have that data and they will provide it, if you ask.
- Sometimes the powder company will limit access to older data in order to promote their latest product. When Accurate discontinued importation of Solo1250, all that data disappeared from their web site and pamphlets in order to promote in-house brands. But you can still get Solo1250 load data today, if you ask.
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AJC1
Member
This is absolutely true. The loads for unique are almost completely absent in the current alliant manual. One could say that they are saving space for other data as those loads are well known. Maybe the best value for the reloader would just be adendums to a base volume that provides only new data, but I dont know the volume of actual testing done to provide new data sets to sell. I would be very interested in powder specific books vise clambering manuals. A 5 or 10 dollar booklet with every load of unique, 2400, blue dot, 4198 and a few others.
Archie
Member
Relative powder burn charts show only the burn speed of individual powders (and usual give the warning this can change in some conditions). Charts do NOT show the relative burning rates of powders.
That is to say, the burn rate between powder #9 and powder #10 is NOT the same as the difference between #23 and #24. (Those are numbers at random.)
I will also mention that powder burn rates are not primarily dependent on barrel length, but the ratio of propellent to bullet weight AND (at the same time, not alternately) expansion ratio.
One must also learn and understand things like 'this' powder can be (historically evident) cannot be reduced in certain applications, but 'that' powder can be so used. I have done some limited substitution of one powder for another when I did not have what I consider prior verified and tested information. I have not had any problems - although once I decided the substituted powder was already at the high end of pressures. One credits this success - should one think of it that way - as an overabundance of caution and God watching out for those who don't know any better. No comment on which was more important.
That is to say, the burn rate between powder #9 and powder #10 is NOT the same as the difference between #23 and #24. (Those are numbers at random.)
I will also mention that powder burn rates are not primarily dependent on barrel length, but the ratio of propellent to bullet weight AND (at the same time, not alternately) expansion ratio.
One must also learn and understand things like 'this' powder can be (historically evident) cannot be reduced in certain applications, but 'that' powder can be so used. I have done some limited substitution of one powder for another when I did not have what I consider prior verified and tested information. I have not had any problems - although once I decided the substituted powder was already at the high end of pressures. One credits this success - should one think of it that way - as an overabundance of caution and God watching out for those who don't know any better. No comment on which was more important.
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AJC1
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Maybe the big issue or elephant in the room is discussion on how to properly use the charts, and what they are really telling you. Is their any published discussion on their proper usage and limitations. Do so many use them incorrectly because we dont have literature available to direct those that are off the reservation. It might be a great opportunity for an article in something like reloader magazine, or maybe it has been done and I'd never seen it. I would instantly add it to my digital archive as a reference to educate.
Burn rate charts only tell if a particular powder is faster or slower than another powder, not how much faster or slower. They are Relative charts. None I have ever seen report the burn speed, just how a powder relates to other powders. I have only found the use of a burn rate chart to see where a powder fits as in "family", but never to determine a powder's use/data...
What actually is wrong with the Hodgdon chart?? Seems very up to date to me but it will never keep up with brand new powders, But I do not rely on any burn rate chart very much.
Burn rate charts are just relative to all the other powders included, so the calculation goes from the fastest pistol powder to the slowest rifle. Which adds all kinds of variance.
Hodgdon online has 163 powders
My Lyman 49th has 114. Don't know about any newer version.
So the relation number is gonna be different.
https://hodgdon.com/wp-content/uploads/2019/11/burn-rate-color.pdf
Burn rate charts are good for ballpark comparisons. This could come in handy during component shortages (like now) where you see a pound of an unfamiliar powder available on the shelf that is otherwise bare. Will that powder work in your application? A burn rate charge will tell you that the powder is appropriate for your application. You don't want that bottle of Lil Gun powder if you need to load for your 9mm gun. But if you come across a pound of 20/28 the burn chart says it would work FOR MID RANGE LOADS.
I also use Quickload as a starting point for rifle loads and endpoint for pistol loads because I usually stay below 80% predicted Max SAAMI pressure for pistol cartridges and look for at least a 90% burn by the time the bullet exits the barrel. When I find a load that looks good with the candidate powder, I chronograph the load and if the predicted MV is close to my measured MV, I feel comfortable with that load for that cartridge.
Quickload was developed for bottle neck rifle cartridges and gets pretty wonky with pistol loads nearing 100% case capacity and short barrels. That makes 9mm tough because the predicted pressures increase significantly with small differences in seating depth of the bullet where in real life, it's not as bad as predicted. I simply stay away from those corners.
I like the Western Powders Burn Rate Chart because it is not a one dimensional chart with all powders in a single column. This chart gives you a better clue as to which powders from other brands come close in burn rates. Because many powders (especially under the Hodgdon umbrella) are in fact the same powders with different labels, this chart will show which powders from different companies MAY have similar burn rates.
Single column charts like the Hodgdon chart give you no clue whether adjacent powders are in fact the same powders (like Hodgdon HP-38 and Winchester 231) or are different powders that may behave differently. Now for mid range recommended loads, the powders should work fine but the single column chart gives you no clue whether a bunch of powders are similar with a small spread or very different with a large spread.
I also use Quickload as a starting point for rifle loads and endpoint for pistol loads because I usually stay below 80% predicted Max SAAMI pressure for pistol cartridges and look for at least a 90% burn by the time the bullet exits the barrel. When I find a load that looks good with the candidate powder, I chronograph the load and if the predicted MV is close to my measured MV, I feel comfortable with that load for that cartridge.
Quickload was developed for bottle neck rifle cartridges and gets pretty wonky with pistol loads nearing 100% case capacity and short barrels. That makes 9mm tough because the predicted pressures increase significantly with small differences in seating depth of the bullet where in real life, it's not as bad as predicted. I simply stay away from those corners.
I like the Western Powders Burn Rate Chart because it is not a one dimensional chart with all powders in a single column. This chart gives you a better clue as to which powders from other brands come close in burn rates. Because many powders (especially under the Hodgdon umbrella) are in fact the same powders with different labels, this chart will show which powders from different companies MAY have similar burn rates.
Single column charts like the Hodgdon chart give you no clue whether adjacent powders are in fact the same powders (like Hodgdon HP-38 and Winchester 231) or are different powders that may behave differently. Now for mid range recommended loads, the powders should work fine but the single column chart gives you no clue whether a bunch of powders are similar with a small spread or very different with a large spread.
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AJC1
Member
True blue and siholloette on that chart are crazy high in my opinion.
bluetopper
Member
Multiple column charts are by far the best.
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AJC1
Member
I have to agree that despite using the lyman chart, the layout of the western chart is far superior.
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I guess I have no clue what the value of a chart even is. So if one powder has a published proven load does that mean the powder right below and right above it is good for that same load? I doubt that. I guess I just use published data and do not experiment outside that. Yes I may go higher or even lower than published data and vary oal but I dont pick a powder from a chart that is "close" to the published data powder on the chart.
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AJC1
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To me it means it has a similar burn rate and should be considered as an alternative in the same application. If the powder you choose sucks in that load powders adjacent in the burn rate chart are your alternatives.
denton
Member
A powder does not have the same burn rate under all conditions. At higher pressure and temperature, a powder will burn faster. Loose, on your bench, it burns quite slowly.
So when you put a sample of powder in the pressure bomb, you're checking burn rate under one controlled set of circumstances.
So when you put a sample of powder in the pressure bomb, you're checking burn rate under one controlled set of circumstances.
bluetopper
Member
Just like differing load data itself, these burn rate charts are just a guide they are not our Bible. They will get you close and in the ballpark.
Blue68f100
Member
Does anybody know if they use the same amount of powder, (1:1) for the test? Since some powders require more or less when compared to another next to each other on the chart.
Powder data from the bullet or powder companies will get you a great deal closer than the ballpark, burn rate charts just get you in the door, tested data finds you the correct seat and a hotdog.
If that be the case, my apologies in advance for the tone of my previous post.
That said, here is a ("somewhat-old-days" standard) closed-bomb configuration/approach for loading density:
https://apps.dtic.mil/sti/pdfs/ADB015387.pdf
Others actually in the business (Denton?) weigh in.....
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I'm not sure that is a given. Maybe moving up or down w/r to burn rate (within the limits of reliable data) would give you better results. One place I like to check when starting something new is the Nosler on-line data. They are a bullet manufacturer so they test powders from all the companies. The loads that they list performed the best in their testing. Certainly a good place to start and give a suitable range of "burn rates".
I've always thought that these charts are somewhat subjective and that is why they don't always agree. I think that not all powders are tested, especially those from other companies, and they place them within the framework of the tests that they do have based on more qualitative data.
Blue68f100
Member
If that be the case, my apologies in advance for the tone of my previous post.
That said, here is a ("somewhat-old-days" standard) closed-bomb configuration/approach for loading density:
View attachment 1049121
https://apps.dtic.mil/sti/pdfs/ADB015387.pdf
Others actually in the business (Denton?) weigh in.....
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That's the info I was looking for. They had to have some reference in doing the test for it to mean anything.
We do a simi-closed bomb every time we load a round.
Ours have a relief valve.
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AJC1
Member
The biggest consideration in these tests is pressure. That drives how the powder acts and why they act differently in our applications. The pressure listed is well below rifle pressure and far above low pressure pistol like 45acp and 38spl. The load tables are really miniature burn rate charts tailored to that specific cartridge.
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