For US, you can own a suppressor if you has a Class 3 License (dealer) or you pay the transfer tax with a Form 4 to ATF to be an individual owner of a suppressor.
For HK, don't think cans are allowed to any individuals even if they have a firearm license.
FHs are defined as suppressor in some states in the US as it suppresses muzzle flashes and noise to some extend. So it is banded in certain area in the US.
But of course it is not as sensitive as other NFA weapons, like a suppressor.
