I've had a low fps problem with a customer's gun that turned out to be both the chamber and rubber.
He had a PDI-W in there, said it was no good. But the gun could barely feed BBs past the lips because they were too tight.
Changed to R-hop and modify flat rubber, same issue. Poorly casted chamber tapered inside and put extra squeeze on the hop rubber's lips. Just sanded them out a bit and it worked great after.
With the rubber in the chamber, it should take a very minimal amount of force to move the BB past the hop rubber's seal
|