I need some help. I have a Sig 239 originally chambered in 357 sig that I bought an after market 40 cal barrel for. I am able to interchange the two barrels to change calibers. I am having trouble with the 357 sig barrel, witch is the factory barrel. The after market 40 cal barrel functions flawlessly. The 357 sig barrel jams in several different ways. It stove pipes, it doesn't shut all the way, it doesn't hit the primer hard enough to fire the cartridge, to name a few problems. These problems happen about 30-40% of the time. I have cleaned the pistol. I have changed magazines and ammo. I have called Sig. I can't find out the problem. I have made a mold of the chamber to determine if there is a problem with dimensions, but I can't find reliable specs on the P239. Does anyone have any idea where to get free specs for the chamber? I have been told that it could be an ammo problem. I believe this, but I have tried 4 different brands. Does anyone know what brand ammo Sig uses when test firing new handguns? Any help would be greatly appreciated.