New AA#9 is Slower

petej88 · March 18, 2002, 09:55 PM

I just started using a new 8 lb bottle of AA#9 that I had bought about a year ago. It looks the same, smells the same, meters the same, fills the case the same. BUT, it averages 100 fps slower than my old #9 that I just finished using.

I've heard that AA has used different factories to produce the powder. I thought that they had cleaned up and settled on one factory?

I used to be able to load 10.7 grains and get 1075 fps or so (4.5" barrel). The new stuff at 10.7 is no stronger than a rat fart. I realize the minimum is 11.7 in the AA manual. At 11.7, it's about the same as 10.7 used to be.

My electronic scale appears to still be calibrated correctly.

Anybody else run into this?

JMC · March 19, 2002, 07:11 AM

The burning rate always varies from lot to lot no matter what brand of powder it is but...Accurate Arms powders do seem to vary the most and this has been one complaint from reloaders from the very first days of Accurate Arms.

I have to say however, 100 fps slower is a big difference.

Peter M. Eick · March 21, 2002, 04:08 PM

I only buy powder one pound at a time due to shipping constraints, so I cannot help much. But, I have noticed a fair amount of variation from my last aa9 order and the current order. Older reloads average a total of 54fps faster then the most recent order. I do not have the older lot numbers (did not used to record that) but I do have the newer lot numbers.

Anyway, it shows why the chrono is so helpful.

Cal4D4 · March 22, 2002, 02:03 AM

http://www.clarkcustomguns.com/460loadchart.htm

Although the warning in the loading info for the .460 Rowland applies to AA#7 it still should give you cause for thought about your powder selections in top loads. AA#7 is listed as THE powder for the .460 Rowland on many sites and tables.

Another url regarding 800X powder gives detailed discussion on what powders are tested for "linearity" in pressure curve as they exceed normal recommended doses. Try a search here for 800X, if you don't find it PM me and I will dig it out.

March 18, 2002, 09:55 PM	#1
petej88 Senior Member Join Date: November 7, 1999 Location: US Posts: 510	New AA#9 is Slower I just started using a new 8 lb bottle of AA#9 that I had bought about a year ago. It looks the same, smells the same, meters the same, fills the case the same. BUT, it averages 100 fps slower than my old #9 that I just finished using. I've heard that AA has used different factories to produce the powder. I thought that they had cleaned up and settled on one factory? I used to be able to load 10.7 grains and get 1075 fps or so (4.5" barrel). The new stuff at 10.7 is no stronger than a rat fart. I realize the minimum is 11.7 in the AA manual. At 11.7, it's about the same as 10.7 used to be. My electronic scale appears to still be calibrated correctly. Anybody else run into this? __________________ http://www.45gap.com

March 19, 2002, 07:11 AM	#2
JMC Senior Member Join Date: March 6, 1999 Location: FL Posts: 809	The burning rate always varies from lot to lot no matter what brand of powder it is but...Accurate Arms powders do seem to vary the most and this has been one complaint from reloaders from the very first days of Accurate Arms. I have to say however, 100 fps slower is a big difference. __________________ Jim - NRA Life Member since '69.

March 21, 2002, 04:08 PM	#3
Peter M. Eick Senior Member Join Date: August 3, 1999 Location: Houston, Texas Posts: 2,991	I only buy powder one pound at a time due to shipping constraints, so I cannot help much. But, I have noticed a fair amount of variation from my last aa9 order and the current order. Older reloads average a total of 54fps faster then the most recent order. I do not have the older lot numbers (did not used to record that) but I do have the newer lot numbers. Anyway, it shows why the chrono is so helpful. __________________ 10mm and 357sig, the best things to come along since the 38 super!

March 22, 2002, 02:03 AM	#4
Cal4D4 Senior Member Join Date: June 18, 2001 Location: southern california Posts: 679	Check this out http://www.clarkcustomguns.com/460loadchart.htm Although the warning in the loading info for the .460 Rowland applies to AA#7 it still should give you cause for thought about your powder selections in top loads. AA#7 is listed as THE powder for the .460 Rowland on many sites and tables. Another url regarding 800X powder gives detailed discussion on what powders are tested for "linearity" in pressure curve as they exceed normal recommended doses. Try a search here for 800X, if you don't find it PM me and I will dig it out.