Two powders of similar burn rate performance

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BJung

New member
I tried test loads using BD for Winchester and Nosler 158 JHP bullets for my .357 and the result was not as stellar as with the Speer 158 GD. I'm thinking of trying AA7 but the burn rate is similar to BD. Will I therefore get the same result. Has anyone tested a powder that performed poorly and then tested another powder with a similar burn rate and the test result was better? I've used AA9 years ago and that was good. I just didn't like the recoil. I would guess that 2400 should be close to AA9.
 
Z

zxcvbob

New member
I have never heard of Winchester BD. (or does that mean Blue Dot?) AA#7 is a good powder for .357 Magnum. I mostly use it with 158 grain cast bullets. I have not compared it directly with 2400 but I would guess 2400 gives better performance but requires more powder. #7 is about like Blue Dot without the drama. Blue Dot gets squirrelly in cold weather, and if you are trying for max loads (even without the cold weather) it can go from okay to case head separations really quick.
 
7

74A95

New member
What performance are you talking about? It's hard to answer your question when we don't know what the question is.

Velocity?

Accuracy?

Recoil force?

Something else?

What?
 
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BJung

New member
For my .357, I plan to load 160gr Lee FRN bullets with AA5 as a target load, thinking that AA7 would be better for the heavier 158gr JHP Winchester and Nosler bullets I have as something close to a factory load. I've tested Blue Dot and it's accurate for the 158gr GD Speer. The temp sensitivity is concerning. Maybe I should change over to AA7 later.

Your opinion comparing AA5 to AA7 for lead bullets as a target load would be appreciated. Thanks
 
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Aguila Blanca

Staff
Could you back up and separate this out into one or more specific questions? So far, in your initial post you tossed in Blue Dot, AA7, AA9, and 2400 without making clear what you were asking. Then your follow-up post brought in AA5, which wasn't part of the original question(s).

Take a deep breath, and try to compose discrete questions so people can try to give you focused answers.
 
M

mehavey

New member
Burn rate is only ONE factor in a powder's ballistic response:

- Burn Rate/sec (and that's only the rate at the start of pressure rise)
- Energy content (Heat/Kg)
- Ratio of specific heats (specific heat at constant pressure vs and the specific heat at constant volume)
- Progressive (or de-gressive) burning rate (with increasing pressure)
- Progressive burning limit (at which point it quits increasing pressure)
- ...and last but not least: a "Factor b" to balance the thermodynamics

As you can see, don't EVER use simple Burn Rate to estimate loading results.
 
Z

zxcvbob

New member
brasscollector said:
Per the OP:
Has anyone tested a powder that performed poorly and then tested another powder with a similar burn rate and the test result was better?
Click to expand...

I have. Blue Dot vs. AA#7 (actually a pulldown powder that cross-references to #7) The Blue Dot performed poorly in almost every thing and the AA7 was good. That may have been my fault rather than the powder because I was pushing the limits.

When I was almost out of BD, I found an awesome load for in it .45 Colt +P and used up the rest of the pound loading that.
 
B

BJung

New member
I tested Blue Dot for my .357. The performance was poor using this powder with Winchester and Nosler 158 JHP bullets. I am thinking about trying AA7 but the burn rate is next to or very close to Blue Dot. Would my future test results using AA7 be the same as BD because of this? I never switched powders with a burn rate so close. Anyone have experience with test loads having burn rates next to each other; one being poor and the other performing well?
 
4

44 AMP

Staff
Similar burn rates are just that, similar, not identical. And there are other factors in play with specific combinations of components.

Similar burn rate powders should produce similar velocities, but other load characteristics can vary, possibly drastically.

your gun, your brass, your primer, your bullet and lot# of powder, expect generally similar results but be prepared for results at either end of the bell curve, and only testing in your gun will tell you for sure what you've got.

I generally load 2400 in .357, because I am looking for full magnum results. I don't shoot mid-range, or light .357s. For that I shoot .38specal and mostly 158 @850fps (approx) using Red Dot, because I have a half keg of red dot to use up. :D
 
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Nathan

New member
Burn rate is only ONE factor in a powder's ballistic response:

- Burn Rate/sec (and that's only the rate at the start of pressure rise)
- Energy content (Heat/Kg)
- Ratio of specific heats (specific heat at constant pressure vs and the specific heat at constant volume)
- Progressive (or de-gressive) burning rate (with increasing pressure)
- Progressive burning limit (at which point it quits increasing pressure)
- ...and last but not least: a "Factor b" to balance the thermodynamics

As you can see, don't EVER use simple Burn Rate to estimate loading results.
Click to expand...

Where do I find that data and how do I use it?
 
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