I ran some of the Zombie Max that I had purchased through my Glock 23 today, and I must say that those rounds were hot! It was significantly louder, I felt the pressure more, and it had way more felt recoil than my Speer Gold Dots or my practice ammo. Awesome thing was, the 165 gr. Z-Max that I used hit exactly at my point of aim every time, and that made me feel really good. Sometime my practice ammo is a bit off (Federal Champion 180 gr.)