I currently own an M&P 40FS with the .357 Sig barrel. I bought the extra barrel because I was gifted about 5,000 rounds of Speer Gold Dot .357 Sig.

I am a retired federal agent, and current firearms instructor. The U.S. Secret Service and the Air marshals are probably the biggest users of .357 Sig ammunition. It is a great law enforcement round for sure.

That being said, when you look at actual law enforcement shooting results, there is a very slim difference between the major LE calibers in use today. Approximately 4 to 6 percent difference in one shot stops.

Basically it's ALL bullet placement! If you don't get a hit in a vital area, you might not get the subject to stop the attack. No caliber will make up for a poorly placed shot.