No, generally speaking, you don’t have to use subsonic ammo with a suppressor. However, you might find that running your suppressed gun with subsonic loads makes for a better experience overall because it does reduce overall sound.
With many suppressor models, it’s up to you whether you use subsonic or supersonic ammunition. That said, some suppressor models do require subsonic ammunition in specific calibers. The SilencerCo Octane and Osprey fall in this category with 300 BLK. If you have questions about this, be sure to ask your qualified dealer or reach out to the SilencerCo Customer Service department.
If your suppressor does not require subsonic ammo in your chosen caliber and you’re trying to decide whether or not to use subsonic ammo in your suppressed firearm, it’s a good idea to consider what you’re using it for. When the gun in question is a defensive firearm, it is generally wiser to stick to standard loads. A defensive firearm must cycle consistently, impact targets predictably at a variety of distances, and be capable of significant energy transfer (which is helped along by greater velocity, among other things). If it’s for hunting, you could easily be fine using subsonic ammo as long as you keep in mind that range will be more limited. As a hunter, it’s your responsibility to make a clean, ethical kill.
