Accurate Arms #9

Disclaimer: All of the following powder charges were taken from reloading manuals produced by gun powder companies or other reloading manuals that may vary in powder charges greatly. Various components combined, make all the difference in the world. I am not responsible for your actions. Always refer to official reloading manuals when reloading. As usual, I must say that this information is what works for me. Use your own common sense. You are responsible for your own actions!

AA #9 may be the most forgiving & versatile 357 Sig powder on the market. I fired over 1500 rounds testing this pistol powder.

1.     AA #9 is a very consistent powder. Even though I use an outside chronograph in the constantly changing weather of Oregon (cloudy, sunny, and rainy all within a 30 minute period), the standard deviation of #9 generally ranges between 5 and 15.

2.     #9 fills the case very nicely and provides some level of bullet setback security (bullet cannot slip all the way into the case) since it works well as a compressed powder. As a result, I do not feel the need to use a light cannelure bullet groove to help hold the bullet in place when using this powder.

3.     An accidental double charge would spill out of the case to warn you.

4.     #9 is a medium flash powder, depending on how it's loaded and what length of barrel it's fired from. My newest lot of #9 is cleaner than the old stuff I was using.

5.     #9 produces very good accuracy.

Accurate Arms Company 800-416-3006; www.accuratepowder.com

Accurate Arms distributes the accurate powder line. The #9 label states, "Accurate #9 Smokeless Powder -- A ball-type pistol powder. Best in .357, .41, .44 magnum. Excellent powder for the .30 M-1 carbine and .410 shotgun". Well, it looks like the 357 Sig fits right in there with the other well-known magnum calibers.

Note: The Accurate Arms Reloading Number 2 Book states that 13.0 grains is the maximum powder charge, while the Speer's Reloading Manual (13^th Edition), states that 14.6 is the maximum charge. Accurate Arms recommends a max of 13.0 grains based on the components they tested in their lab environment. Speer stated that their loads were developed on standard test equipment and did not exceed the 40,000 psi maximum. So if you approach the Accurate Arms 13.0 maximum and beyond, be very careful. The individual components you use can make a huge difference! With hard jacketed bullets, I would stick with a maximum of 13.0 grains as AA recommends.

NOTE REGARDING DIFFERENT LOTS OF #9: With my newest lot of #9, I cannot load less than 11.7 grains, otherwise the load becomes very inconsistent. With my old #9, I could drop to 10.7 grains and it worked flawlessly. Also, with my new #9, I cannot put more than 14.0 grains in the case, as opposed to my older lot where I could put in 14.6. The velocities of the newer lot are also roughly 25 to 35 fps slower. As a result of these differences, I have removed my light loads less than 11.7 grains, to cut down on confusion.

A brief quote from the Accurate Arms Reloading Book:

"Reports from the field praise the accuracy of this round [the 357 Sig]. Our #9 has proven to be well suited for this round. This is without a doubt the most ballistically consistent handgun cartridge we have ever worked with. The standard deviation for every single load developed was less than 10 FPS. The average SD was 5 FPS. This is impressive for any cartridge but especially so for a handgun. The small bottleneck and high working pressure of the round must both contribute to this amazing consistency."

Note: OAL refers to Over-All Length of the cartridge.

357 Sig OAL normally runs between 1.120 to 1.140, based on various reloading manuals and from measuring various factory ammo. 

Glock 31 with standard 4.5" barrel

Starline brass

Winchester primers

West Coast 124 grain flat point bullets

OAL: 1.137

Please see NOTE REGARDING DIFFERENT LOTS OF #9 above. I used my new lot of #9 for the above chart.

Steyr M357 with standard 4" barrel

Starline brass

Winchester primers

Rainier plated 124 grain flat point bullets

OAL: 1.140

+E = Energy in ft-pounds; ++P.F. = Power Factor

Steyr M357 with standard 4" barrel

Starline brass

Winchester primers

Rainier plated 124 grain flat point bullets

OAL: 1.126

Steyr M357 with standard 4" barrel

Starline brass

Winchester primers

Speer Gold Dot 125 Grain HP

OAL: 1.139 average

As a comparison, here's the results of shooting Factory Loaded Speer Gold Dot HP Ammo. The factory ammo proved to be almost as consistent as my reloaded AA #9 ammo J . By the way, Speer Gold Dot ammo is really excellent factory ammo!

I did a simple 21 ft. accuracy test to make sure the Gold Dot bullets were flying true, to protect my beloved chronograph. All of the Speer loads grouped in 1" patterns or less.

Since I used new Starline brass and a tight case mouth, I lightly chamfered the case opening to get rid of any little burrs, etc. Seating an unbeveled bullet like a Gold Dot into a new tight case takes some care.

Glock 35 with standard 5.32" barrel

Starline brass

Winchester primers

Rainier plated 124 grain flat point bullets

OAL: 1.135

+E = Energy in ft-pounds; ++P.F. = Power Factor