357 SIG Gold Dot & AA#9 test

[petej88]

357 SIG reloading data:
Steyr M357 with standard 4" barrel (note: A Glock's polygonal rifling would increase velocites around 5% or so.)

Starline brass
Winchester primers
Speer Gold Dot 125 Grain HP
OAL: 1.139 average

Grains, High Velocity, Low Velocity, Extreme Spread, Average Velocity, Standard Deviation,
13.5 1314 1287 27 1297 10
13.7 1329 1318 11 1322 4
14.0 1345 1326 19 1337 7
14.3 1371 1351 20 1361 7
14.6 1409 1389 20 1400 8

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 . By the way, Speer Gold Dot ammo is really excellent factory ammo!

High V., Low V., Extr sprd., Av. V., Std Dev.
Speer Gold Dot HP 1337 1303 34 1321 11

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.

Note: Making a strong crimp on a compressed bullet can actually lengthen the OAL by another few thousandths inch. Therefore, you may wish to bell the case mouth little if at all, so the bullet fits snugly. Then, especially for full loads, you may wish to make a very light crimp since the bullet is being held up by the powder anyway. In this way, you may find it easier to keep the cartridge below or equal to the 1.140 OAL SAAMI maximum. Some pistols, like my Steyr M357, can operate well over the SAAMI OAL max. So, for your particular pistol, make sure your cartridge has the correct dimensions, that it can chamber correctly, and that it can cycle correctly before making a bunch of rounds.

Also, 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.

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[kidcoltoutlaw]

i love the way power pistol shoots in the 357 sig with the speer gd 125.but for the sake of saftey it looks like i should try the a # 9 is it accurate ?????????? i no the power pistol is a real tack driver in my sig 357 sport. but only at max loads.

[petej88]

Well, I'm not a bullseye shooter. But I can say that AA#9 appears to be accurate for my combat shooting, from 10.7 to 14.6 grains --- that's a heck of a spread for a powder by the way.

I've done bullet setback testing from one end of the #9 spectrum to the other and could not cause any case damage or high pressure signs.

Just recently, I did a 10.7 grain #9 test with a bullet setback measuring 1.042 OAL! The Glock 31 held its own fine and there were not high pressure signs. Normal OAL is 1.135. Once again, the bullet setback oal of 1.042 is a huge difference from the standard 1.135. This is awesome.

[kidcoltoutlaw]

works well in the 357 sig and fills the case a plus when it comes to bullet setback.works very well in 147 speer gold dot.i get very little spread from left to right but sometimes i string shots a little up and down i think its just me i have trouble getting locked on the target.im still shooting under 2 inches at 25 yards and sometimes well under 2 inches but if i could fix the up and down problem i would be well under an inch.what target works best for shooting groups.