Bcwitt
Member
Not a dumb question. Dont listen to anything but good proven tested data. Everyone thinks they know everything, even when they dont. It's your face that it's going to blow up in, who do you trust? Use good data only.
Powder Burn Chart Question
- Thread starter Wyo82
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Right? I saw someone say something in a forum, and It made me think so I asked a question. Instantly it’s inferred that I’m out at my bench with no loading manuals, never looked up data, just a big ol copy of a burn chart and I’m just cranking hot and heavy loads out. Not the case - just a question!!!
Charlie98
Member
Everyone knows something... even if it's their own experience, or something they read. It may be right, it may be wrong, or somewhere in between. I've seen comments about how you shouldn't believe anything you read on the internet forums, but I've also seen gross errors in print, too. I've gotten a lot of good information from the forums... but you have to filter it with other data, too. I've asked a lot of 'dumb' questions in my time... I've gotten some even dumber answers as well.
When starting a load work up, i usually look at what powders the load data shows will give me the velocity range im looking for. There will be several powders that give me the velocity i want and then i go into temp stabile or not. For the creedmoor h4350 is considered the best all around powder because it gives decent velocity and is very temp stable. The burn rate chart is just 1 reference to use giving you a general idea of how the powder will perform. Heavy for caliber bullets tend to like slower powders.
As mentioned above, burn rate charts are not linear, but relative. Powder 33 may be faster than powder 34, but how much? Powder 33 is relatively faster, but not by a specified amount and the difference may be huge if there is no other powder available/manufacturer that fits between the two. Also, #33 is probably slower than #32 but not by the same burn rate as #33 vs #34...
I've been reloading for a long time and if I can't find specific load data I believe there is a reason why. Mainly because the powder or combination of components are nor really compatible to safe/consistent reloading. No big deal for me because I always found a load in a published reloading manual before I purchases components...
I've been reloading for a long time and if I can't find specific load data I believe there is a reason why. Mainly because the powder or combination of components are nor really compatible to safe/consistent reloading. No big deal for me because I always found a load in a published reloading manual before I purchases components...
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Charlie98
Member
That's why I posted the link to the Accurate chart... the first time I saw that chart and really looked at it, about a dozen lightbulbs went off in my head, and it sent me careening down the path to understand further the relationship of burn rate and ballistics. I just wish someone would post an updated version of it... to include the newer powders that are available.
denton
Member
ADI puts out a chart that shows approximately equivalent powders from various manufacturers. If you're trying to find a substitute powder, it is very helpful.
http://www.adi-powders.com.au/powder-equivalents/
http://www.adi-powders.com.au/powder-equivalents/
Skeptic13
Member
I do like the burn rate chart from accurate better that the first one posted. I like to see the manufacturers side by side. I will often look at the chart and the powders around the one I like to see what is in the same range as the powder I can't find. However I would never buy one of those powders until I have checked with the powder manufacturer to see if they recommend that powder for the caliber and bullet weight I am loading.
Bcwitt
Member
Agreed. Just making the point to know what your doing before you put your eye out.Everyone knows something... even if it's their own experience, or something they read. It may be right, it may be wrong, or somewhere in between. I've seen comments about how you shouldn't believe anything you read on the internet forums, but I've also seen gross errors in print, too. I've gotten a lot of good information from the forums... but you have to filter it with other data, too. I've asked a lot of 'dumb' questions in my time... I've gotten some even dumber answers as well.
Yep. I normally warn new reloaders to ignore any load data, and to verify info they see on a forum. There is a lot of good info on line but also a bunch of bad info posted as "gospel". The main problem with this is newer reloads haven't developed their "BS filter" to take the good and toss the bad. Better to err on the side of caution and find reliable data/info from known professional sites (tool manufacturers, powder manufacturers and distributors, known publications) and just think of everything else as entertainment ...Everyone knows something... even if it's their own experience, or something they read. It may be right, it may be wrong, or somewhere in between. I've seen comments about how you shouldn't believe anything you read on the internet forums, but I've also seen gross errors in print, too. I've gotten a lot of good information from the forums... but you have to filter it with other data, too. I've asked a lot of 'dumb' questions in my time... I've gotten some even dumber answers as well.
Bcwitt
Member
Important to remember, a rate chart is based on what the industry refers to as a closed bomb test. A "faster" powder might be slower then a supposed slow powder used in a different chamber shape. It's a useful tool, but not an exact science. Use modern published data. Always.
Charlie98
Member
Much has to do with what type of powder it is, and it's general composition... that's quite true. Just like chronograph data, a burn rate chart is not an End All in load workup... they are all just pieces of the puzzle, but you need as many pieces as you can get to see the bigger picture.
Bcwitt
Member
Well said.
Reloadron
Contributing Member
This is a thread dating back to 2009 on the subject where some good points are made. Here is a quote from an old VitaVuori reloading pamphlet which precedes their burn rate chart. "Current cannister powders in order of approximate burning rate. This list is approximate only and not to be used for developing loads". My career for the most part was devoted to test engineering but I have no clue as to how burn rate testing of cannister smokeless powder is performed. I simply cannot find a published test procedure or method. The link I posted allures to that. SAAMI, ANSI or any others list a test method and procedure. Every now and then a list is published normally adding new powders and removing powders no longer in production. Even looking at current list, as mentioned, list are not always in agreement. Obviously using a powder burn rate chart for load development is not a good idea. From time of ignition to bullet exiting the case is pretty quick, in many cartridges including rifle ignition to bullet exit barrel is 0.002 seconds and often much less. There is a whole lot happening in a real short time interval. Today's electronics using chamber pressure sensors is really pretty cool stuff. Rather than measuring a copper slug compression we can actually plot the pressure curve and note how fast a powder reaches peak pressure. I would stick with published load data.
Anyway if anyone had some good and credible dope on how burn rates are actually measured I would really like to read what you have.
Ron
Anyway if anyone had some good and credible dope on how burn rates are actually measured I would really like to read what you have.
Ron
Bcwitt
Member
The principal method is called a closed bomb test. I'll try to find you some more info.
Reloadron
Contributing Member
That turns up in the link as suggested by RCmodel. I had planned to follow up on that, just out of interest. When you really think about it there is a hell of a pile of variables to consider. Pretty cool stuff and thanks for posting it. Pretty interesting stuff out there.
Ron
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Bcwitt
Member
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Bcwitt
Member
This is from Mettalic Cartridge Reloading M.L.McPherson circa 1996. I have more written on it also, but just had this reference handy.
Reloadron
Contributing Member
Thanks and I like that they present the method and results. The 1984 brought back some memories too as to the equipment used. Pretty cool and thanks again for digging that up and sharing it.
Ron
chamokaneman
Member
Good thread.
I'm currently thinking about loading some 130 grain Speer HP's in a 308 Winchester. I can kind of understand why I'm NOT finding much/any published loads for the RL-19, RL-22, and IMR4350 I have but DO see some things I can probably use for faster powders I have like TAC,Varget,H335, and IMR4320. Which one to try first?
I guess this is related to the OP's question....is there a protocol to follow for choosing the best published load for your equipment among several choices or just try stuff until you find what works best?
I'm currently thinking about loading some 130 grain Speer HP's in a 308 Winchester. I can kind of understand why I'm NOT finding much/any published loads for the RL-19, RL-22, and IMR4350 I have but DO see some things I can probably use for faster powders I have like TAC,Varget,H335, and IMR4320. Which one to try first?
I guess this is related to the OP's question....is there a protocol to follow for choosing the best published load for your equipment among several choices or just try stuff until you find what works best?
Reloadron
Contributing Member
You pretty much find what works best. That being best in any particular gun.
Next, load manuals aside yopu can always go online to powder manufacturers and get their suggested load data for a particular bullet on a particular cartridge. You can also email them seeking advice for a specific powder in a load. While Re15 and Re12 show up for the Speer 130 grain #2005 they do not list Re19 or Re22. That could be because it was never tested or because it is simply not recommended. Normally we choose a powder from a published data source and work a load up starting low and adding powder but not exceeding a maximum load. When a powder simply won't group well I move to another powder and repeat the process.
Rpn
Charlie98
Member
Generically speaking, lighter bullets go with faster powders, heavier bullets... slower. I load 110grn Hornadys in .308, I use IMR3031. For that matter, my standard 150grn .308 and .30-06 load is either IMR3031 or IMR4895. Given what you have on hand, H335 and maybe Varget or TAC, assuming you can find data. (Hodgdon's online data has both H335 and Varget for the 130grn Speer.)
rfwobbly
Member
There is absolutely no way to know. This is because the powders are simply listed in order of speed. But the incremental steps between each listing vary wildly.
The next "slower" powder could have a difference increment of zero or 200, you simply don't know. What you need to look at is a relative burn rate chart, like THIS ONE.
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