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I have a Five Seven and PS90. My Five Seven is my nightstand gun. I bought it after my son was born. 5.7 ammo was designed to not over-penetrate a target. The 197 fragments even more on hard targets. That is what is in my gun. It will penetrate far less interior walls than a regular handgun round.
Also, some ballistic tube tests posted by a member on our site showed respectable results. Some people who have used the round for hunting also talked about the results of what the round did. I'm impressed enough to rely on the gun.