As someone who recently started loading .357 SIG for my XDm, a few tips to help you out. The LEE dies are excellent for the SIG, they are the correct dimensions. Make sure you go ahead and get you a .40 LEE carbide die as well to size the body first, then the SIG die to shape the shoulder. This will keep you from having to lube the cases and clean them again. Also get the LEE factory crimp die because trying to crimp and seat at the same time in the SIG can be a hard thing to get right, especially if you use multiple type projectiles.
For powder, Longshot & Power Pistol give you magnum like performance as the cartridge was designed to do (ballistics of a 125 grain .357 Magnum in a semi auto platform. Both powders have the velocity and accuracy down pat. Also, AA#9 is a great powder as well. Many use it due to the fact it fills the case almost completely which keeps the bullets from setting back in the event that neck tension should fail. I use all three powders and love them all. AA#9 will give you the least amount of velocity, but is still a great powder. All 3 powders in my trials burn clean.
For projectiles, Xtreme 124 RNFP work very well and are cheap enough you can plink with. They tend to be pretty accurate too. Speer 125 grain Gold Dot (SIG profile) work very well too! They are accurate and its what LEO use every day and depend on for their lives. The Hornady 124 grain XTP work very well just like the others. They are accurate, even more accurate in my gun than the Speer. Something I dealt with when loading that I'm not sure as to why it happened is belling the cases just right... The Xtreme didn't need any belling at all, though I belled just a tad bit.. the Speer required a good bit of belling, or they would seat off center and crush the cases.. the XTP seated very similar to the Xtreme and didn't need much belling at all. It was tough to find the happy medium when setting my powder die on the Dillon to where they all did well without losing neck tension or being to tight to seat properly. Also a lil tip with the LEE dies, since I have them set up on my Dillon, I took a fine tip Sharpie to mark each position with for the different projectiles so switching between them is easier to find the right position to return to the correct seating depth for each one.
Hope this helps. The SIG is a fun round to shoot, POA at 10-50 yards is a blast... aim and send it!
Reply With Quote