The hop in your airsoft gun is to increase your BBs range significantly. It does this by utilizing the Magnus effect. When the BB passes through the hop up chamber, there is a nub, that sits on the bucking when this nub presses down it protrudes through the barrel’s window pressing down on the bucking’s inner mound, in turn a passing BB hits this and is spun backwards. The backwards spin rotates the BB in the opposite direction that gravity pulls on it.
Adjustable Hop Ups Most hop ups are adjustable; this means you can adjust the amount of pressure the hop up arm presses on the nub, giving you more or less back spin. This matters when you change BB weights, a heavier BB will usually require more back spin to maintain a straight trajectory. The opposite story goes for lighter BBs. As well as the guns power, so the user can tune the gun right where it needs to be.
Hop Up Buckings Hop Up buckings are sleeves that slide onto the end of your barrel, this piece serves two main purposes. As talked about earlier, the nub rests on top of the rubber (or silicone) bucking which sits on top of the AEG’s barrel window (a cut out open space in your barrel). Your AEGs hop up arm presses down on this nub protruding through the bucking into your AEGs barrel window.
In addition to that your bucking also services as a BB stopper. They prevent BBs from rolling out the end of the barrel. You will sometimes notice, that at the end of fire your airsoft gun, with the hop up turned all the way to normal (or down) the next BB in line to fire will roll out of the barrel when the muzzle is facing down.
Bucking material and "hardness" Soft and hard buckings soft type buckings are more popular they are generally more consistent as far as accuracy goes. However when you really crank up the power in your airsoft gun a harder bucking may be required. The reason is because the gun will require more backspin for a straighter BB flight path and the soft bucking material will get warn down at a quicker rate than a stiff/sturdy hard bucking.
Buckings come in a wide variety of material, color, shape, etc. There are a lot out there you need to find the one or brand that suits you best. *Buckings are a wear and tear item and need to be replaced over time.
Nub: The small cushion of rubber (or other material) that gets pressed down into the bucking this is connected by your hop up arm. Nubs come in a variety of shapes and sizes, something I will not get into at this time. There is a lot of different hop up units, buckings out there, some are designed to serve additional purposes, however the end goal is the same.
