General silencer discussion. If you want to talk about a specific silenced rifle or pistol, it is best to do that in the rifle or pistol section for that brand.
The M4-2000 has more volume in the rear, and thus has a somewhat softer sound than the Ranger. When metered to Mil-Spec, we typically get -34dB with the M4-2000 and -31dB with the Ranger.