J
Jhart
Guest
I have been going through some burn rate charts and i have noticed that there all different.. Can somebody tell me who has the most accurate data on this subject.
They're all different because there's no such thing as an "accurate burn rate chart," they're all approximations.
Also, powders act differently under differing conditions.
Your choice IMO is to use loads directly from the manuals, matching EVERY component or learn how to work up your own loads, carefully and safely. Making extrapolations from a burn rate chart can be dangerous, start low and assume nothing. Chart velocity with a chronograph and look for a smooth pressure rise as charge wt rises...... if it starts to plateau look out.
If you are working around a plateau and your day ends, do not just start the next day where you left off. Back off a grain.
Free advice, worth exactly what'cha paid......
al
Also, powders act differently under differing conditions.
Your choice IMO is to use loads directly from the manuals, matching EVERY component or learn how to work up your own loads, carefully and safely. Making extrapolations from a burn rate chart can be dangerous, start low and assume nothing. Chart velocity with a chronograph and look for a smooth pressure rise as charge wt rises...... if it starts to plateau look out.
If you are working around a plateau and your day ends, do not just start the next day where you left off. Back off a grain.
Free advice, worth exactly what'cha paid......
al
Wayne Shaw
Active member
Al is right. Burn rates that are listed are a rough guide at best.
Take the BR case. The characteristics vary greatly from the 22BR to the 30BR, just by changing the exit hole size and bullet weight. What one would think "should" be about right, may not even be close to what works.
The only thing to do is start low and go up, it's been said many times, but you have no other choice.
Take the BR case. The characteristics vary greatly from the 22BR to the 30BR, just by changing the exit hole size and bullet weight. What one would think "should" be about right, may not even be close to what works.
The only thing to do is start low and go up, it's been said many times, but you have no other choice.
M
Montana Pete
Guest
I thought it was interesting that the Speer Manual #14 refuses to list a burn rate section on powders because -- so they say -- of the extreme danger of using such charts to either mix powders or substitute powders.
Some of my older manuals have such charts. I find them useful to quickly determine what's faster than what. For example, is Red Dot faster than Green Dot?
Some of my older manuals have such charts. I find them useful to quickly determine what's faster than what. For example, is Red Dot faster than Green Dot?
H
hecksf
Guest
I normally use the Hodgdon chart since they seem to update their data as oftern as any of the manufacturers, but every now and then I question the results.
I wish that SAAMI would produce their own chart each year.
Ted
I wish that SAAMI would produce their own chart each year.
Ted
2
.25shooter
Guest
Burning rate charts
I find them useful when loading for cal that you dont have much data about like wildcats and such. However say if you have developed your max load with one type of powder you do not automatically assume that you can load the same amount of powder of another type just because it is one place slower than the first powder. But loading some 10% less (with the same bullet) should be safe and start from there.
I find them useful when loading for cal that you dont have much data about like wildcats and such. However say if you have developed your max load with one type of powder you do not automatically assume that you can load the same amount of powder of another type just because it is one place slower than the first powder. But loading some 10% less (with the same bullet) should be safe and start from there.
Bob Kingsbury
New member
Burning rates are not developed in rifles, they are developed in a closed
container, call it a sealed vault. That 20 grains of powder X raises
pressure to 10,000psi in .2 microseconds and powder Y raises it in
.25 microseconds , places them differently on a chart. In a rifle,
that vault is a continuously changing volume. As the bullet moves
and the volume increases, the pressure goes down, but is relative
to how fast the bullet can move .When all the variables are added
in, the same lot of powder in two different guns doesn't always do the same
thing.
container, call it a sealed vault. That 20 grains of powder X raises
pressure to 10,000psi in .2 microseconds and powder Y raises it in
.25 microseconds , places them differently on a chart. In a rifle,
that vault is a continuously changing volume. As the bullet moves
and the volume increases, the pressure goes down, but is relative
to how fast the bullet can move .When all the variables are added
in, the same lot of powder in two different guns doesn't always do the same
thing.
Boyd Allen
Active member
Learned something new
L
Larry Elliott
Guest
On top of all this, if you look at various manuals for various cartridges of different bore size and similar case size or the same bore size but different case size you'll notice the burning rates can change significantly. Powders will flip positions and/or move up or down enough to cause problems if someone just looks at a burning rate chart and dives right in.
The charts are a reasonable place to start if little or no data is available, but a guy has to pay close attention AND know what signs of high pressures are.
Also some powders change burning rates considerably from lot to lot. If they're slower it only means reduced velocities, if they're faster it can mean a stuck case, stuck bolt, or worse.
The charts are a reasonable place to start if little or no data is available, but a guy has to pay close attention AND know what signs of high pressures are.
Also some powders change burning rates considerably from lot to lot. If they're slower it only means reduced velocities, if they're faster it can mean a stuck case, stuck bolt, or worse.
Well said Larry,
There was a time when I had all the reloading manuals and wind charts and burn rates basically memorized...... I saw that some of the charts disagreed, even FLIPPED rates, but put it down to sloppiness, bad data. I was "planning my ultimate gun"..... actually several guns..
I set out to prove the rest of the world WRONG..... to remake the rules."Everybodies blind" I said....
"Nobody wants to step out" I said.......
"Folks are stick-in-the-mud traditionalists" I said.......
"There is no such thing as "inherently accurate" I said .........
"So many things can be fixed with proper forethought" I said.......
"There's no reason to make sacrifices, I can have it ALL" I said.......
"Start from scratch, plan well and run the numbers" I said.... "with the information available to us today there's NO REASON to compromise, just buy the best of everything based on BC's and Burn Rates and build it like a race car"......"Tailor a cartridge to each caliber and you should be able to come up with "The System" wherein one can have a stable of maybe 3 well-designed rifles that will just do it ALL"
mebbeso 5yrs and at least $10,000.00 later, poorer and 'umbled.... I regrouped and admitted that my presumptions were nearly universally wrong!
And one thing that went 'WAYYYY out the window during all this is "Burn Rate Charts"......... I absolutely agree with everything said so far on the subject, FINE points made by all in this thread.
IMO
al
T
Tony Shankle
Guest
I have been using this one lately... http://www.reloadersnest.com/burnrates.asp
Not because I trust one over the other but because I look for the one with the most powders. Since I am going to start low and work up I just want the most options and it makes me feel better to see the newer powders listed.
Fuzzy logic but I am sticking with it!
Not because I trust one over the other but because I look for the one with the most powders. Since I am going to start low and work up I just want the most options and it makes me feel better to see the newer powders listed.
Fuzzy logic but I am sticking with it!
J
Jhart
Guest
Thanks
Glad i asked.... While im asking questions answer me this,,What is the little black square at the top of our benchrest targets for...
Glad i asked.... While im asking questions answer me this,,What is the little black square at the top of our benchrest targets for...