I just bought a brand new non-railed P229 in .357sig.  The only way I am going to shoot that cartridge is if I roll my own, so I'm looking into the specifics of reloading .357sig.  If I decide against it I'll just sell the barrel and replace it with one chambered in .40S&W.  I haven't looked into the manuals I have yet (I will), but there doesn't seem to be a lot of load data online (unless I'm just missing it).  Can you guys give me any tips or suggestions in reloading this cartridge?  I have 3K 115gr. FMJ 9mm (.355) boolits, and a good amount of 231 and Power Pistol powders.  Will I be able to utilize any or all of those components in reloading .357sig?  I have Lee 4-die carbide sets in 9, 40, and 45.  Are Lee dies good for .357sig, or do you recommend something else?  I would be reloading single-stage with my RCBS RC.

Thanks for any help!

Mike

I don't remember the charge I used but Power Pistol works nicely in .357 SIG.  My two Glocks are now .40 S&W.

ernief

Read some of THIS,, good tip in 1 of the replies..

If you have SPEER cases, use a #2 center drill to open the flash holes before running through size die...

Run them through a carbide 40 S&W die first to do the body of the case... then through a SIG die for the neck size...

I load lots of sig ammo using lee dies the biggest problem I've run into is make sure to use a good case lube lee lube has worked the best for me , ruined first set of dies using spray lube it damaged the sizing die and started to scratch cases, also try not to load to much nickel brass harder on the dies. Bullets I usually try to use .356 diameter but have used .355 with no problems just keep checking neck tension on bullet.For powder I use n350 its clean and meters well and gives good velocity and accuracy. Load em up and enjoy its a fun caliber

I load a lot of this cartridge.
Power pistol would probably be fine, not the 231. Also your 115 gr bullets should not be used.
Rainier 125 gr flat points work great. You need the strait edge of the bullet for proper hold.
(there isn't much neck to hold it) I used to use Zero brand, but they have become too hard to get.
The bullet needs to look like this:

/  
I  I
(hopefully you get the idea... looks like a house)

Use a powder that gives a full case (to/near the shoulder) helps prevent set back.
I use Longshot (8.5 gr) and have great accuracy & VERY low extreme spread (25 fps).

I "body size" with a LEE .40 carbide die, then "neck size" with a Hornady .357 SIG die. (no lube required)
I treat the cases as "rifle" cases....
"meaning" I do NOT use the "belling die".  Instead, I chamfer the mouth.
The cases do not grow in my experience (unlike bottle neck rifle cases)... so this has been a "1 time step".
(I've loaded the same case 3 times so far & they are still fine)
I did some testing after a bunch of research and found this method gives the strongest neck tension.

Hope this helps... and yes, speer has small flash holes)

I reloaded 357 Sig for a while about 10 years ago, I did it on my RL550 and I used the Dillon die set.

Power Pistol worked great for this round.

That shoulder can be a pain in the ass at RL550 speeds.

i reload 357 sig.  not sure if the sig has rifling or hexogonal barrel.  Spray lube is good, but i had a harder problem finding the correct projectile.  a reg 9mm RN will not work.  not enough shoulder to hold bullet in place.  I ended up with a 9mm truncated cone and i was good to go.  i cast for 357 sig.  i think i use Accurate #5 or #7

good luck

Thanks guys for all of the good suggestions!  

Mike