I have a Javelin M4 RIS and the whole gun is stock. But the hop up unit and bucking is bad. What kind of hop up and bucking should I get? p.s the guns specifications are - 370 - 385 fps - 6.05 -6.06 mm inner barrel - wired to the front RIS handguard (not sure if you need those last two ones but just to be safe.) Thanks!