How many suppressor mounts do I need?

One suppressor mount per suppressor. You’ll then be able to use the suppressor on any rifle that has a Hellfire (or Sidewinder, if you went that route) adapter.

IMPORTANT NOTE: If your can mount is a Hellfire mount, it’ll only work with Hellfire adapters. Same goes for Sidewinder mounts – good for Sidewinder adapters only. They’re cousins, but they don’t share dimensions.