The S&W M&P 22 is definitely threaded. They even give you a little wrench for taking the end-cap off the barrel. It might not look like it at first glance, but the entire barrel actually is clad in a full length barrel shroud. You can take off the end cap, and replace it with an adapter like this that will then let you attach something like a compensator or muzzle brake.
Brownells has the gemtech adapter.
but will they ship?



























