Tanaka M700 Hop issue

[Four Leaf]

Hi everyone,

Have recently installed a kings arms VSR conversion kit with a G&G metal hop chamber and a nine ball VSR rubber.

Now when I shoot the gun the bb either doesn't come out the barrel, then when I tip the gun it rolls out, or it shoots out with no hop at all applied, hitting a wall about 25 meters away, but I can see the drastic dip that implies the hop isn't putting spin on the BB.

I've tried putting the hop all the way on and off and nothing makes a difference, it's either one extreme or the other.

The BB's are shattering when they hit the wall and a chrono with .25's shows it as shooting at 400 fps.

Any ideas anyone ?

Ta, FL