Our T2PB Karnivor main spring is an OEM replacement for your worn out or rusted stock main spring / hammer spring. If your current main spring is worn out and has lost tension over time and you are having difficulty chronoing or getting the correct velocity, this is a cost effective solution. Compression springs wear out over time and eventually lack the tension necessary to propel your hammer. A worn out main spring requires more regulator pressure to propel your paintball. Higher regulator pressures can cause brittle paint to break inside of your gun. Replacing your main spring allows for a flush IVG and fixes low velocity issues.