I'm a bit late to this thread, but wanted to add my two cents. I've found a Power Pistol load that pretty much mirrors what Ben from Alliant's CS said (see previous post). The load is 5.1 grains of Power Pistol, a Federal SP primer, and a 125 LRN from Missouri Bullet Company.
The load is easy on the hand, easy on the gun, and chews out the center ring of a target at 15 yards. At 25 yards, off-hand, I get 3.5" 5-shot groups. This is all out of an XD9 Service.