Mike, I just went thru this exercise w/ an SP-01. My barrel my be slower down here in Cincy vs. Cleveland (lol), but it required 4.0g of HP38 to get good groupings. I've since switched to 3.8g to VV N320 (just a tad hotter) because I feel it meters more accurately. Like IDescribe indicated, target a higher PF, CZ's like faster rounds to be accurate. My most accurate load has a 137PF at 1.13 OAL behind 135g SNS bullets.