AA#9 lot variation8

[crkckr]

I recently aquired 3 pounds of AA#9 powder to go with the pound I bought in 2006 and have been using for various hot loads in .357 Mag and .44 Mag. Just a couple of years ago I got into 10mm and I've pretty much settled on #9 as my go to powder in that caliber, so I purchased 3 pounds recently. However, in testing some loads today, I got a difference of 132 fps between the new lot compared to the old lot! I've been reloading since I was 17 or so and I'm 72 now so I've been doing this for a while, which is why I tested the different lots. However, I've never seen this much of a difference before, including lots of powder that had a much larger spread in age. There is no degradation of the 2006 lot, in fact, in all the years I've been reloading I've had exactly 1 lot of powder go bad, a pound of IMR 4198 that I'd had for umpteen years. I've got powders that after 30 years still shoot just fine. I store my powders in an old upright freezer that had the compressor go out and a new one was the same price as a new freezer, so I ripped all the guts out, sealed everything up and now use it as a powder magazine.

As to the AA#9, I'm liking the new lot! I'm getting 1450 fps using 15.5 grains of AA#9 under a Speer 165 gr. Gold Dot bullet (Speer #15 says 1344 fps), while the 2006 lot is only giving me about 1315 fps. There are no pressure signs in either set of cartridges. I'm thinking the old lot is on the lower side while the new lot is on the higher side of the tolerances.

Any comments?
Cheers,
crkckr

 

[Cecil S.]

AA#9 is my go to for Pistol. Think my stock is from the newer stock.

 

[crkckr]

For 10mm, it's the same for me. I got a reply from Hodgdon, who said that my 2006 lot of powder was made in the Czech Republic, so they have no idea! I'm doing a bit more testing tomorrow. I ran a couple more rounds over the LabRadar today and got 152 fps average difference, so there's clearly a gap between the two. All of my SD ammo will be loaded with the new stuff! I've just never seen this much of a spread between lots, although they both seem to provide about the same pressures, according to the cases. Then again 10mm has been the hardest cartridge I've ever dealt with when it comes to pressure signs. Either that or this Starline brass is tougher than nails! It is good brass, I got 19 loadings out of two (of ten, the others are still going) while doing load work ups... and I didn't start light, either. The 2 cases developed neck cracks and had to be tossed. I like that!
Cheers,
crkckr

 

[243winxb]

#9 357 mag data is all over the place. Powder was made in many different countries. Many different photos here-
https://www.ilrc.ucf.edu/powders/sample_detail.php?powder_id=17.
Same with Accurate no 5.

The good news is, Currently, Hodgdon gets it from St Marks in Fla. So lot to lot variations should be less?

You should test for powder position sensitivity. Powder against prime vs powder at bullets base.

I use a magnum primer.

 

[crkckr]

I'm using magnum primers but doing some testing with regular Win primers that say for standard & magnum but a true mag primer (I use CCI & Federal 155's) does make a big difference. My 10mm 165 gr load of 15.5 gr of A#9 fills the case pretty full once the bullet is seated so I don't think there can be any position differences in the powder. The only time I've done position testing is when using I started using 38 Special and .44 Special loads in magnum cases. Turns out there's so little difference in case volume that the lightest 'special' loads work just fine in the magnum cases. Been doing that for over 30 years. As it stands now I don't even have any 44 Special cases and the only reason I have any 38 cases is because of a couple of 38 revo's stuffed way back in the safe. I even take 'em out and look at them once in a while!
Cheers,
crkckr