sig 357 barrel from Sig Sauer. 1 had ran 150 rounds down the barrel with zero failures. Not sure of first owner round count. Convert your 40 cal to a 357 sig with just barrel swap. New cost $180 + tax and or shipping. Email me at email@example.com. Pick up in Rockwall. Awesome deal at $70 dollars! These are hard to find and work in either gun Thx!