I have some more beginner shooter questions regarding handgun target/practice 9mm ammo. I have a Glock 19 (Gen 4) and a Walther PPQ M2 that I use. My questions are: 1. During the post-Sandy Hook difficult-to-find-even-9mm days, I found & bought a couple of boxes of Winchester 9mm NATO rounds. How are these different from regular 9mm rounds? And would you recommend firing this through any of my handguns? Or will the ammo damage my gun in any way? 2. The cheapest practice 9mm round that I can find are the Federal Champion Aluminum cased rounds from Walmart. But since they are aluminum casings and aside from not being able to reload them, do any of you not recommend firing them from my gun? Are they harmful to the gun in any manner? 3. What about steel cased ammo such as Tulammo? Do any of you not recommend using this kind of ammo due to any possible negative effects on my gun, short or long term? 4. Finally, do any of you have any recommended or favorite target 9mm ammo? And what's the reason for your recommendation? Thanks in advance for all your answers.