NFA Weapons (Machine-guns, Suppressors, etc)
Can I legally possess a machine gun in Colorado? CONDITIONAL YES.
Colorado law has no additional prohibitions for NFA weapons (that are not in place by Federal law). Many municipalities/counties have a standing policy that their law enforcement officials will not sign Form 4's, but that's rare. Denver, of course, has that policy, as does Douglas County.
For an FAQ about the Federal laws, click here for Bardwell's excellent primer.