The aluminum nozzle slides really smoothly within the bolt, much smoother than the stock plastic nozzle. I have 4 more aluminum nozzles arriving for testing with RA-Tech's new steel nozzle guides.
Here is a video of the aluminum nozzle in action:
RA-Tech Aluminum Nozzle for WE M4/M16 GBBR (Airsoft) - YouTube
FPS Values with 0.20g bbs
487.2
491
487.2
485.3
484.2
425.8
495.6
500.2
487.2
508.3
487.5
499.5
508.3
507.3
485.3
Looks pretty consistent to me... except for the odd outliers..Im not really worried about the high fps as I can tune down the NPAS (I'll dial the npas all the way down to see what is the lowest FPS for for the purpose of gaming), im more interested in the consistency from shot to shot..