Two powders of similar burn rate performance

BJung · November 15, 2020, 11:06 PM

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.

zxcvbob · November 16, 2020, 12:21 AM

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.

74A95 · November 16, 2020, 12:43 AM

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?

BJung · November 16, 2020, 01:42 AM

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

**Aguila Blanca** · November 16, 2020, 03:01 AM

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.

mehavey · November 16, 2020, 07:16 AM

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.

BJung · November 16, 2020, 10:49 AM

Thanks Aquila. I think Mehavy answered my question.

74A95 · November 16, 2020, 12:32 PM

Quote:

Originally Posted by burbank_jung

Thanks Aquila. I think Mehavy answered my question.

And we still don't know what the question was.

brasscollector · November 16, 2020, 12:54 PM

Per the OP:

Quote:

Has anyone tested a powder that performed poorly and then tested another powder with a similar burn rate and the test result was better?

zxcvbob · November 16, 2020, 01:04 PM

Quote:

Originally Posted by brasscollector

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?

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.

BJung · November 16, 2020, 01:11 PM

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?

**Aguila Blanca** · November 16, 2020, 02:12 PM

What performance criterion was poor? Velocity? Accuracy/precision? Fouling?

T. O'Heir · November 16, 2020, 02:34 PM

"...I would guess..." No guessing is required or advised. Burn rate charts are readily available on line. This is one. They're all pretty much the same.
http://bulletin.accurateshooter.com/...download-here/
"...2400 should be close to AA9..." Nope. 2400 is #54. AA#9 is #57. Isn't about the burn rate though. It's about the data you can find. 2400 is typically a cast bullet powder. AA #9 is not.

**44 AMP** · November 16, 2020, 03:02 PM

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.

BJung · November 16, 2020, 03:27 PM

Performance meaning any of testload groupings.

Nathan · November 16, 2020, 04:13 PM

Quote:

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.

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

mehavey · November 16, 2020, 08:52 PM

It's what QuickLoad uses to make its (quite accurate) predictions of ballistic (internal & external) results.

While Helmut has default values from actual bomb tests for all powders in his file, each profile can drilled
down into and adjusted based on your own rifle/powder lot/conditions, etc.
See https://thefiringline.com/forums/sho...0&postcount=15

.

November 15, 2020, 11:06 PM	#1
BJung Senior Member Join Date: December 5, 2019 Posts: 773	Two powders of similar burn rate performance 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.

November 16, 2020, 12:21 AM	#2
zxcvbob Senior Member Join Date: December 20, 2007 Location: S.E. Minnesota Posts: 4,720	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. __________________ "Everything they do is so dramatic and flamboyant. It just makes me want to set myself on fire!" —Lucille Bluth

November 16, 2020, 02:12 PM	#12
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,457	What performance criterion was poor? Velocity? Accuracy/precision? Fouling? __________________ NRA Life Member / Certified Instructor NRA Chief RSO / CMP RSO 1911 Certified Armorer Jeepaholic

November 16, 2020, 02:34 PM	#13
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	"...I would guess..." No guessing is required or advised. Burn rate charts are readily available on line. This is one. They're all pretty much the same. http://bulletin.accurateshooter.com/...download-here/ "...2400 should be close to AA9..." Nope. 2400 is #54. AA#9 is #57. Isn't about the burn rate though. It's about the data you can find. 2400 is typically a cast bullet powder. AA #9 is not. __________________ Spelling and grammar count!

November 16, 2020, 03:02 PM	#14
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,790	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. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

November 16, 2020, 12:43 AM	#3
74A95 Senior Member Join Date: November 26, 2016 Posts: 1,564	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?

November 16, 2020, 01:42 AM	#4
BJung Senior Member Join Date: December 5, 2019 Posts: 773	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

November 16, 2020, 03:01 AM	#5
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,457	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. __________________ NRA Life Member / Certified Instructor NRA Chief RSO / CMP RSO 1911 Certified Armorer Jeepaholic

November 16, 2020, 07:16 AM	#6
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,882	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.

November 16, 2020, 10:49 AM	#7
BJung Senior Member Join Date: December 5, 2019 Posts: 773	Thanks Aquila. I think Mehavy answered my question.

November 16, 2020, 01:11 PM	#11
BJung Senior Member Join Date: December 5, 2019 Posts: 773	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?

November 16, 2020, 03:27 PM	#15
BJung Senior Member Join Date: December 5, 2019 Posts: 773	Performance meaning any of testload groupings.

November 16, 2020, 08:52 PM	#17
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,882	It's what QuickLoad uses to make its (quite accurate) predictions of ballistic (internal & external) results. While Helmut has default values from actual bomb tests for all powders in his file, each profile can drilled down into and adjusted based on your own rifle/powder lot/conditions, etc. See https://thefiringline.com/forums/sho...0&postcount=15 . Last edited by mehavey; November 16, 2020 at 09:17 PM.

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