M4/ M16 Collimator Kit
This is the direct replacement for the rubber bumper on the USMC Infantry Weapon Collimator (IWC). It's compatible with most similar style rubber bumpers on 5.56mm collimators. Note that the purpose of the bumper is to ensure that the collimator mandrel is inserted into the barrel at the proper depth, so it's important that you use the correct bumper. If you're unsure, please contact us.