Hi D
to test the modify spring compairison chart, I built an AEG mechbox using mainly parts from the list.
using a Tm m733 body with said mechbox and a Promethus 433mm inner I achieved 375 FPS with the 100.
Chrono and cans M733 style Part 2 - YouTube
as Debriefs aeg is now sporting a 363 madbul running a Similar set up I was expecting 324 with the slight leak from the Piston head (going to change to a high quailty Oring).
Debrief just let me know the nozzle is a modify which explains why it works better with the Modify dual oring Cylinder thats in there now
What modify nozzle was in there when you shipped it?
AK, M4??
I red recently that the Modify Sigg nozzle is the closest to a stock G&G UMP nozzle