If your hop-up adjustment is not having a big effect on the hop-up of your BBs, then it probably means that your hop-up packing is worn down and is not gripping the BB properly before it is fired out. A new hop-up packing will allow more accurate hop-up adjustments. This hard type packing is designed to match high power upgrades at 400fps+. High power upgrades require a harder hop-up packing since softer material may deform from the higher power. However if your gun shoots below 400fps, then stay with the soft type packing since otherwise this hard type will not grip the BB properly on low power configurations. Especially recommend to use this hard type hop-up packing onto upgraded sniper rilfe as well for improving semi mode shooting effectively.