Quote:
Originally Posted by StrikeFreedom
I don't think the vents on the piston head affect FPS. The BB has already left the barrel when the blowback process begins. The ported piston head improves the air seal during the blowback, thus yielding better blowback response and gas efficiency.
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So basically, piston heads with vents > piston heads without vents. Ok, that's good to know. The SD piston head seemed to be putting out better numbers than the Nine Ball, which is what made me wonder. Here's a short video I shot using the current setup:
- 6.01 inner barrel
- Nine Ball piston head
- Nine Ball enhanced floating valve spring
- Nine Ball hop up rubber
- SD POM set
- Enhanced floating valve
VIDEO HERE
The readout:
Chronograph: Xcortech 3200
Projectiles: 0.25g BBBastards (black)
337.6
000.0 (did not read)
324.1
330.1
328.7
328.8
325.3
328.4
324
321.5
321.8
324.8
317.6
316.2
High: 337.6 FPS / 1.32 Joules
Low: 316.2 FPS / 1.15 Joules
Average: 325.3 FPS / 1.22 Joules
Translated figures using FPS calculator if I was using 0.2g BBs:
High: 376.84 FPS / 1.32 Joules
Low: 351.74 FPS / 1.15 Joules
Average: 362.29 FPS / 1.22 Joules
In earlier tests I had the exact same set up, but instead of the Nine Ball piston head and enhanced floating valve and floating valve spring, I had the SD piston head and stock floating valve and spring. My shots were more consistent, and I also achieved more power. The results are on
page 35 of this thread.