Subsonic Ammo.
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Subsonic ammo travels below the speed of sound, which eliminates the sharp supersonic crack and makes suppressed shooting dramatically quieter. It is popular for .300 Blackout, 9mm and .22 LR, for home defense, hunting and backyard plinking. At Gunners Outlet we stock subsonic ammunition when it is available, including heavy .300 Blackout loads and quiet .22 LR. Order online and we ship fast from our New Hampshire warehouse.
How Subsonic Ammo Works
The speed of sound is about 1,125 feet per second at sea level. Bullets faster than that create a small sonic boom. Subsonic loads stay below it, so with a suppressor you mostly hear the action cycling.
To keep energy up at low velocity, subsonic loads usually use heavier bullets: 147 grain in 9mm and 200 to 220 grain in .300 Blackout. In .22 LR, standard velocity and quiet loads like CCI Quiet-22 are naturally subsonic or close to it.
Because subsonic rounds generate less gas, some semi-auto rifles and pistols need tuning to cycle them reliably. Test your load before relying on it, and choose bullets designed to expand at low velocity for hunting or defense.
Frequently Asked Questions
300 blackout subsonic vs supersonic: which is better?
Subsonic .300 Blackout is much quieter suppressed, while supersonic loads shoot flatter and hit harder at distance. Choose subsonic for suppressed use, supersonic for range and hunting.
What is the best subsonic 300 blackout ammo?
The best subsonic .300 Blackout ammo uses a 200 to 220 grain bullet designed to expand at low velocity for defense and hunting, or FMJ for practice.
Do you need a suppressor for subsonic ammo?
No, subsonic ammo works in any firearm chambered for it, but its quiet advantage is most noticeable with a suppressor.
Is 147 grain 9mm subsonic?
Most 147 grain 9mm loads are subsonic or very close to it, which makes them a common choice for suppressed pistols.