Load Ideas
Brass is available from Starline, using small pistol primers. My powders of choice are Accurate #9, Power Pistol and Unique with the first two powders being used for full power loads. With Unique and Power Pistol I use #500 CCI Standard Pistol Primers, however, just as with sixgun loads, I switch to #550 CCI Magnum Pistol Primers with Accurate #9. My rule of thumb for handguns is to use standard primers on loads found on the burn rate chart up to and through #2400 and then switch to Magnum primers after that. Using Magnum primers with #9 in the .357 SIG results in much smaller extreme spreads.
My bullets of choice are the Hornady 115-XTP JHP, 124-XTP JHP and the 147-XTP JHP BT (boat tail). From Speer, I like their 115- and 124-Gold Dot HPs. My most-used factory load is the SIG 125-V-Crown JHP clocking out at 1,325 fps from my pair of SIG .357 SIG pistols. This load is duplicated with 8.7 grains of Power Pistol with either the Hornady or Speer bullets.
My most accurate reloads for the SIG .357 3.9" Model 229 Legion would be the Hornady 124-XTP and 115-XTP, both over 8.7 grains of Power Pistol, (1,330 fps and 1,325 fps); and the Hornady 115-XTP with 13.5 grains Accurate #9, clocking out at 1,374 fps. All loads will shoot into 1" for five shots at 15 yards.