Originally Posted by The Spiritus Raptor

well, typically when you chrono to get a fps spread, you cannot shoot fast... aka 1 shot and read, one shot and read, etc. Shootdown wouldnt be an issue in measuring spread, but I have seen that too much tension on the rear spring is not good for consistency. You should make your rva as soft as possible actually, as this has an effect on the bolt, and bolt motion (it's attached to the hammer), resistance to the air resetting the hammer, and probably more that I'm not thinking of right now. Excessive pressure on the hammer causes the valve to be open too long, leaving more time for air based inconsistencies, and contrary to belief, the fva matching the powertube really doesn't make a difference. I get a +/- 8 spread, and I have that sucker almost all the way in (about a turn and a quarter from being bottomed out). Also, if you drop your input pressure to right around 700, it makes it a bit more consistent... anything more or less and it seems to make the spread larger.... hope this helps you dude, this is how I got mine to where it is... and its with a CMI inline reg (~40 bucks, but the only other one other than palmers that can handle liquid co2 properly).