The 357 sig produces some impressive ballistics but it does so at the cost of high pressures and increased muzzle blast. I got a LW 357 sig barrel for my Gen 2 G23 and bought some relatively inexpensive 125 grain FMJ PPU (Privi Partisan, Made in Serbia) and the first time I shot it I tried the gun first with the 40 caliber ammo, (Speer Lawman 180 gr FMJ) and then swapped barrels and tried the 357 sig ammo. The 357 Sig appeared to have a little sharper recoil than the 40 and there was noticeably more muzzle blast. I later found out that the PPU ammo is loaded very hot and is rated at 1542 FPS while most 357 sig 125 grain ammo is loaded to 1350 fps. The Cor-bon 125 grain JHP ammo is loaded to 1525 fps. I haven't tried reloading for it yet but I suspect that it may be difficult to safely approach those top velocities. I also found out that the 357 sig operates at a higher chamber pressure than 9mm or 40 S&W, 40,000 PSI for the Sig vs. 35,000 for the 9 and the .40. My thinking is that this round is probably optimum for concealed carry in something like a G32 but I'd like it even better in the single-stack G43. But for home defense it's got too much muzzle blast to be shooting indoors in close quarters in a stress situation with no hearing protection.