[Zfurlong]

Lrb-long range barrel mod, drilling the outer and using screws to cause the inner barrel to bend just ever so slightly in a given way so the BB rides along the top of the inner barrel.
Er-hop - extended r-hop. Done by cutting the hop window longer and using a longer r-hop patch.
TDC mod - top dead center mod. Done by drilling and tapping directly above your hop window, and using a screw or something at the end of the screw to ensure perfectly centered pressure on the hop rubber ensuring a perfect hop every time. These mods are discussed in detail over on airsoft sniper forum