Wrong, do some homework. If a bullet has less "grain" it will be lighter, meaning that the bullet will travel faster but with less "knock-down power" (because it is a lighter bullet). The higher the grain, the heavier the bullet, this results in a slower bullet but more "knock-down power".
I know that the more grain a bullet has, the faster it is. It has more power in the sense that it will travel further, faster. The less grain, the slower the bullet. I use 258 grain hollow point in my 357 so when I have to use it, it will have the knock down power and leave a coffee can size hole in you at the exit site. You'll have a bad day if you force me to protect myself.