Systema Bore Up Cylinder Type-4 for Marui MP5-K

Systema Bore Up Cylinder Type-4 for Marui MP5-K Metal Construction Design For Upgrade the Origianl Parts More Durable Suitable For Tokyo Marui MP5-K Series Airsoft Rifle This is a highly recommended upgrade for AEGs with lengthened barrels since you will need additional volume of air to propel the BB out of the longer barrel - to avoid back-pressure. These bore-up cylinders actually have the same external dimensions as a stock cylinder so they will fit into a standard gearbox.