[HKGhost]

It's because of the lip on the Modify hop up bucking. It's a bit tighter than others and stiffer. Take out the bucking and place a bb onto it. Try pushing the bb through and you'll discover that it takes more pressure to push the bb through than other buckings. If you really want to use that bucking, there are two ways to get it to work. 1) stretch the lip with a bb and quickly run a lighter around the lip. This will expand it a bit. Install it, then use silly oil to keep it slippery and run a mag through it (basically you're breaking in the bucking). 2) Mod the tappet plate so the nozzle pushes the bb in farther into the bucking. You only need to take off 0.5mm off the front of the tappet plate. And an added bonus, this will give you a much better air seal. This is what I did. Hope that helps.