Here's a link to some results and discussion about Pinnacle:
http://forum.hunting.net/asppg/tm.asp?m=1000611Pinnacle is made by American Pioneer (CleanShot) for Goex, so you have to figure it's the same powder, just a darker color. As such, you'll find the 2fg to be 5 to 10% weaker than Pyro RS. I would definitely go with the 3fg cut of Pinnacle and for pistol shooting, expect that 5 to 10% drop in power and velocity when compared to Pyro P or Black 3fg.
The good thing about Pinnacle is that it IS clean shooting powder - the difference between it and black or Pyro is significant.