There are Suppression Collars and Suppression Rings that are made with all Nine Schools, and can stop a person from using magic, but those aren't what you're looking for. Not merely that, but there's a Magical Material, Orichalcum, which has the same function as a Bolt of Law/Prime; basically, it's able to go through magical shields (but not matter) and damage even high-level Magi. Too bad only the Agency knows about it, and has equipped its Nonmagi members (and Magi who don't have Law) with it.