[ILLusion]

The most I'd ever gotten out of a 5.1" Hi-Capa was around 315 fps with .25g BBs. Equivalent fps at that power using a 0.20g BB would be roughly 352 fps.

Parts related to power output in that build would be:
- PDI 6.01mm inner barrel
- 9Ball Hop Up rubber
- RCC Power Up Cylinder Bulb
- KM High Flow Valves

Note: If you actually fired a 0.20g BB out of that setup, your FPS would be lower. Roughly 335fps.

That fps isn't far from my current builds. I can get roughly 320-330fps with 0.20g BBs using Tanio Koba Twist barrels, Firefly hop up rubber, Action power up cylinder bulb, and KM high flow valves.

Gas is inconsistent, and they're are many factors that can skew consistency of results.
For example, a couple of times, while messing with a bone stock Marui MEU, I was putting out 310+fps with a 0.20g BB, consistently, when they're only rated for 290fps. It could have been the way I was filling the mags, or how I let the mags rest before using them. The ambient temperature may be different as well.