I have used Blue Bullets 180's and N320 at 4.8 grains at 1.17 OAL to get around a 172 - 174 PF out of mine. I'm sure I could drop a bit and still make major no problem, but usually try to come in around 172.
I also chrono'd this weekend with the same specs, only with WST being the powder. 4.8 grains still came in right at 172 PF.