The 357 SIG was designed to get the ballistic equivalent to the so called "best" self defense handgun round,the 125 gr 357 mag revolver round, out of a semi-auto handgun. It comes very close to doing so, the 35 foot pounds of difference at the muzzle is pretty much inconsequential. I know two officers who have used them in the line of duty and they were impressed with them. A couple others who carry it have used it to finish off car hit deer and feel they work better than other calibers they have used. I myself have reservations though they are unfounded so far. It has to do with a bottlenecked cartridge in a revolver. My previous experience with this type of cartridge has been in the S&W 53 in 22 Jet. It is a necked down 357 and is very picky on having clean chambers. If the chambers weren't spotless, the cartridge backed out and froze the cylinder. This experience has left an impression on me that carries over to the SIG round (30 Mauser too). It may be an unreasonable phobia but confidence in one's equipment does play a role in this area. I'm more of a straight walled case kind of guy.