Hi, Gypsy.
The power factor of 150 applies to both rifle and pistol ammo. Most rifle ammo that I have seen chronographed at major events goes well beyond 150 - but that is the standard.
If you shoot SB at Winter Range or EOT, your pistol and rifle ammo will be choreographed, and your pistol weighed with an empty magazine inserted. They fire 5 shots over the chronograph from each firearm. I load my ammo to provide a bit of a cushion, because ammo may perform differently than it did at home, depending on temp and altitude. 149.99 fails!