I apologize a tiny for hijacking but its somewhat relevant to the topic at hand.
I have a KA p90. bone stock, it chrono'd at 380fps with .2
I swapped to a 6.03 450mm element (I know...) and it still chrono'd at 380fps at Rock the Ridge 2.
Then I swapped to an A+ demon hop up rubber and prowin aluminum hop up unit with the same 450 barrel. FPS is all over the place. some shots were around 350, some were 280, some as low as 190. I didn't touch the gear box or the cylinder.
So then I got rid of the prowin hop up and tried the a+ hop up rubber only and it was still being really inconsistent.
I am using .25g BB bastards so I know the BBs can't be at fault. And the barrel is clean. Any idea what could be causing such major variances?
Imagine Whirled Peas