SMC9 Drop in FPS

[acemace021]

As title states got the gun last week which’s look smart, on site fired at 315FPS on Nuprol 4.0

 

The issues started when fitting tracer at the time I didn’t realise that the tracer was pushing back the unique hop adjustment which essentially put hop up on full.

 

so I managed to print a little ring to allow me to screw on the tracer without fouling the hop-up

 

got home this week and using the built in chrono within tracer i’m averaging 250fps, so decided the problem must the rubber which I changed, but still no

joy as to why the fps has dropped.

 

Anyone got one and had this or similar issues or knows what it might be?

 

Thanks in advance