Hop up buckings & Nubs

The Hop up Bucking is the part in the hop up chamber that eventually makes contact with the bb as soon as it is shot into the inner barrel. Because the bb makes contact with the bucking the bb gets spin and that determines the flight of the bb.

There are several buckings on the market, think of Cold Resistant buckings, hard type and soft type buckings but also bucking where the stiffness is indicated in degrees like 50, 60, 70 or 80 degree buckings.
The lower the degrees the softer the bucking, the higher the degrees the harder the bucking.