.357 SIG powder selection

[Telperion]

(cross-posted on TFL while we were down, but I'll ask here too)

I started loading .357 SIG with AA #9, based on recommendations that it was the premier powder for .357 SIG, but the results have been less than satisfactory. Lots of muzzle flash; pistol, clothes, and shooting bench get covered in unburned powder, and it's less accurate on paper than factory loads. Is it that #9 is too slow?

Does anyone have experience with using Power Pistol, VV N340, N350, or 3N37 in .357 SIG? How well do they meter, and what level of muzzle flash do they create? Any other powders that I ought to consider? My goal is to push a 125 gr bullet at 1350 fps to match the SD ammo I use.

 

[JDGray]

I love Power Pistol in 9mm, meters great, good performance at starting load levels. Very accurate. Dont know why it wouldn't perform in 357 sig

 

[EZred]

I have been loading .357SIG for about five months since the acquisition of a 2022. I have tried several different powders and have loaded mainly 124gr XTPs. It seems to favor Blue Dot and most recently I have had really good performance from AA#7. I also broke down and bought a Lee Factory Crimp Die which has really improved consistency.

 

[Dave P]

aa7 is ok for medium loads. Power pistol is fine, but don't overload it!

I got a cheap can of old aa#9, and 13 grains works fine for ranier 124.

 

[ReloaderFred]

What are you shooting 357 Sig in? I've got a Springfield XD and Witness in 357 Sig and they both love AA #9. As posted, 13 grains of AA #9 and a 124 grain bullet is deadly accurate in my XD, but my Witness prefers 115 grain bullets for accuracy.

A firm neck hold on the bullet and solid crimp will help ignition, but you will get some unburned powder. It seems to be the nature of the beast.

I've used Power Pistol in 357 Sig, and it produces more velocity, but AA #9 was more accurate. Blue Dot will also work, but it's kind of temperature sensitive. In warm weather, pressures go up with it.

Hope this helps.

Fred

 

[Telperion]

The issue of crimping didn't come to mind. I am using a Lee FCD. How would I check whether the crimp is adequate?

 

[ReloaderFred]

For best results in the 357 Sig, I like a cannelured bullet and the crimp should go into the cannelure. I've got a CH knurling tool and I put a cannelure on all the bullets that don't have one for this caliber. It makes a big difference in powder burn, but you'll still get a little unburned powder on the bench.

With the Lee Factory Crimp die you should be able to turn the spindle down a little at a time until you finally start to push the shoulder. When that happens, back off about 1/8 turn and see if they're coming out right and will still chamber correctly. A firm crimp is essential with slow powders, along with good neck tension on the bullet.

Hope this helps.

Fred

 

[jethro75]

+ 1 on the stong crimp and neck tension. I use 11.9 grains of AA#9 and rainier 124 fps. Get great accuracy in my glock 32.

 

[ChuckE]

My favorite .357 SIG load:

Pistol: SIG P226 Stainless
Barrel Length: 4.4"
Powder: Power Pistol - 8.0 gr.
Case: Starline
Primer: Federal GM200M Small Pistol Magnum Match
Bullet: Speer 125 gr. TMJ/FN

Trim Length: 0.860"
C.O.A.L.: 1.135"
Crimp: 0.378"

Dies: Redding
Press: Forster Co-Ax Single Stage

Temp: 75F

Avg. Velocity: 1351 fps (10 rounds)
Standard Deviation: 10.24 fps
Extreme Spread: 29 fps
Power Factor: 169

Accurate, burns clean, meters well [but I always weigh each charge and trickle up to exact weight]. Bystanders notice the muzzle flash, but I never do.

Note: Federal uses their #200 magnum primer in all their factory 357 SIG ammo. Most reloading manuals list the standard Federal #100 primer. You need to drop your powder charge about 5% when moving from the #100 to the #200 primer.

Chuck

 

[trueblue1776]

I've been loading for a while now, could somebody telly me what powders benefit form a magnum primer in the .40/.357 cases?

I have had excellent luck with Longshot in those two cases with light bullets. Heavy bullets seem to make too much pressure before you get any awesome results.

 

[Shoney]

trueblue1776: for the 40 S&W, go to the Vihtavouri powder load info. Just go to
http://www.lapua.com/index.php?id=833

then pull down the "HandgunReloadingData2006.pdf"

Check out the load data for N105 with 200 gr bullet. I use Montana Gold bullets as practice rounds and 200 XTP's for PD.

 

[threefeathers]

I've loaded with several of the above powders with good results. Then I trued New Unique. Wow. It is the Daisy for the 357 Sig

 

[Hoosier Reloader]

I've been using AA#7. I haven't tried Vihtavouri yet.

 

[gandog56]

I use AA #9 for my 10mm's, but Unique for my 357 Sigs.

 

[Dave P]

"How would I check whether the crimp is adequate?" I try to push the bullet into the case with my thumb, on a hard floor. Should not budge.

 

[kidcoltoutlaw]

Powder Pistol when you have the need for speed. Like 1555 in a P226 with a G.D 125. Bluedot when I am loading for IDPA.