which powder burns faster/slower?


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gofastman
October 9, 2011, 12:19 AM
2400 or AA#9?
I have looked at a couple different burn rate charts and have conflicting answers

bonus unrelated question:
is AA#9 the slowest powder for 10mm Auto?

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Hondo 60
October 9, 2011, 12:25 AM
Which is worth more 2 nickels or a dime?

They're so close that even the so-called experts can't decide.
Anyway, for what it's worth, Hodgdon, which makes neither, says 2400 is a hair faster.

GP100man
October 9, 2011, 01:21 PM
AA#9 is comparable to H-110 in speed , 2400 is a tad faster & more tolerable to down loading .Maybe down loading is`nt the rite word , broader band of good operating pressure , there fixed !!!!

A slower powder would be IMRs 4227 for the heavies .

But no data with that powder though.

Here`s alink to Hodgdons site http://data.hodgdon.com/cartridge_load.asp

Have fun ,BE SAFE !!!

Walkalong
October 9, 2011, 09:30 PM
Burn rate charts are relative. Powders behave differently in different calibers. Two powders close to each other on the burn rate chart may flip flop depending on caliber.

Since I do not load 10MM, I can not give any input on which is "faster" in that caliber.

rfwobbly
October 9, 2011, 10:20 PM
Since I do not load 10MM.....

What? There's a caliber Walkalong doesn't own? :evil:

GP100man
October 9, 2011, 11:31 PM
Most report good results with IMRs HI SKOR 800X.

Done alittle searchin & 4227 may not be fast enuff to cycle the pistol at the rite time ???

Steve C
October 10, 2011, 12:46 AM
FWIW load data usually shows approximately 1.0 grain less in a start and maximum AA#9 load than the same bullet with 2400 in the .357 mag. That indicates that AA#9 is a tad bit faster.

ArchAngelCD
October 10, 2011, 01:21 AM
I thought AA#9 was a bit faster than 2400 but like said above, powder burn rate is caliber specific.

gamestalker
October 10, 2011, 03:01 AM
Burn rate is relative only to the cartridge application being used. Example, H-110 in a .270 win. cartridge would react as an extremely fast burning powder, where as in it's intended application as a magnum wheel gun powder, it is about the slowest burning powder available.

Those burn rate charts are of no real use in my opinion. May be someone who knows something I'm unaware of, can justify their purpose?

kingmt
October 11, 2011, 05:49 PM
Burn rate is relative only to the cartridge application being used. Example, H-110 in a .270 win. cartridge would react as an extremely fast burning powder, where as in it's intended application as a magnum wheel gun powder, it is about the slowest burning powder available.

Those burn rate charts are of no real use in my opinion. May be someone who knows something I'm unaware of, can justify their purpose?
That just doesn't make since. Using it in a rifle doesn't make it faster. There is actually more air space in the .270 & it will take a lot more powder for it then the .357Mag.

I find burn rate charts very useful in developing loads & going off the map. I just picked one chart & go with it but if one powder is in place 39 & the other is at 40 then they are the same rate.

Walkalong
October 11, 2011, 08:26 PM
That just doesn't make since. Using it in a rifle doesn't make it faster.No, it doesn't, but is is extremely fast for a rifle caliber, which is his point I believe.

kingmt
October 12, 2011, 05:01 PM
You can make more use of slower powders in a rifle but faster powder is still faster regardless if it is used in a rifle or pistol.

I don't know if one powder changes burn rates more then another depending on chamber dimensions or if they are so close it is just where they wrote it down.

Kosh75287
October 14, 2011, 10:19 PM
I'm BETTING that mean chamber pressure of the load/round in question will alter the burning rate of powders also. I don't know where the threshold for altered burn rates is, but I can easily imagine the burn rate of, say, RedDot, being very different for a .38 Spl target load (perhaps 3.0/RedDot/158SWC) vs. a .357-level load (say, 5.3/RedDot/158SWC). I suspect that Alliant Power Pistol might be more illustrative of the effect, though I hasten to add that I've never worked with it.

Fishslayer
October 14, 2011, 10:42 PM
Not all those burn rate charts were calculated under identical conditions.


Those burn rate charts are of no real use in my opinion. May be someone who knows something I'm unaware of, can justify their purpose?

Ummm... I dunno... Maybe to find out how fast one powder is relative to others?:rolleyes:

Something not on the burn rate charts is pressure curve, IE, how does a powder react to increased pressure. Titegroup leaps to mind as a touchy powder. Blue Dot used to be the same way, tho I'm told the new formula is less so.

I would suggest you might have some reading to do...

GaryL
October 15, 2011, 12:05 AM
Like Walkalong pointed out, burn rate varies with application. A slow powder may be too slow for a light bullet but good for a heavy bullet in the same caliber. The heavier bullet causes the pressure to increase and the powder burns faster. The best evidence of that is to pour a small amount of powder on the ground and light it up. I promise you it will take longer to burn unconfined than it would to burn than an equivalent amount in a firearm.

I find a burn rate chart is useful information, but only as a guide. If I have a specific application, I may choose a slower or faster powder for a number of reasons.

Regarding AA#9 or 2400, I like 2400 a lot more for 44mag, and AA#9 (or H110) for small rifle applications.

kingmt
October 15, 2011, 05:53 PM
Those burn rate charts are of no real use in my opinion. May be someone who knows something I'm unaware of, can justify their purpose?

If you only read load data & copy it then I would agree. Most of my powder there is not much to no data for. I have to find out what powder it acts like then find it of the burn rate chart & see what other powders it is like. Then I may look at someones load data to see where I want to start instead of starting all over for each cartridge I want to try it in. I still normally see how low & high I can go but I only stick 1 bullet instead of 20.

Shade Tree Welder
October 15, 2011, 06:04 PM
Powder burn rates are a function of pressure. The burn rate changes faster
or slower as the pressure increases, some of this is the difference between
flake, spheical and extruded grains and grains some of the difference is due
to the composition of the powder, single base vs. double base.

Some pistol/shotgun powders which typically see less than 20 kpsi;
will burn much much faster in a normally moderate 30-40 kpsi rifle
round. So if you sellect a powder from the "relative burn rate chart"
(I hate the things because they can get the unknowning in alot of
danger) your actual chamber pressure can be 60-70 kpsi and result
in the rupturing/failure of the rifle chamber, possibly injuring or killing
the shooter or spectator.

Becareful when going outside of published data.

Walkalong
October 15, 2011, 08:39 PM
They are useful for picking another powder to try that might work in the same application, or showing that a powder is way too fast or slow for an application, but that is about it.

They use a "closed bomb" test to rank them in burn rate. Not really very similar to loaded rounds.

GrayDog
October 18, 2011, 07:16 PM
Here's a link to the Western Powders burn rate chart. It's the one that's always made the most sense to me.

http://www.accuratepowder.com/wp-content/uploads/2010/12/burn_rates.pdf

Note the qualification at the bottom about "approximate burn rate envelopes".

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