A few years ago I had occasion to test handgun penetration against some "bulletproof" glass - 12 ply glass about 4" thick. We tried everything we had from 22 LR on up through 9mm, 40S&W, 44 mag., 45 ACP, etc. The only round that would penetrate all the way through was the 357 SIG 125 gr. Gold Dot. I was impressed! It's a great round and I like it a lot.

Having said all that, i hear today that the Texas DPS, one of the early adopters of the round, is dropping it for the 9mm. Word is they find it easier to train new shooters, gun life is longer, expense is lower, and with modern bullets and loads they believe it will be just about as effective. Time will tell and I'm sure there will be lots of debate, but it will be interesting to see how this develops over the next few years.