What is subsonic ammunition

[guy82901]

This might sound like a stupid question. I am just developing and interest in guns in general and have seen several companies marketing "subsonic" ammunition. Knowing what I know of retail with years of experience as well as science, it seems to me that this is just a marketing trick, as technically any ammunition that has a muzzle velocity of under lets say 1100 f/s is subsonic.

I am curious if there is a difference, or just an excuse for higher prices. I have seen some brands that say it will lower the sound of a shot in any gun, and others say it really only works with suppresors. WHAT IS THE TRUTH????

:banghead:

Thanks for tolerating my questions, probably more to come.

 

[CleverNickname]

Supersonic ammunition produces noise two ways, from the explosion of the gunpowder, and from the supersonic crack the bullet makes in flight. Subsonic ammo will eliminate the supersonic crack. However, the gunpowder is the loudest noise, so using subsonic ammo in a unsuppressed firearm really doesn't lower the noise all that much.

A suppressor muffles the explosion of the gunpowder, but not the bullet's supersonic crack. A suppressed firearm shooting supersonic ammo is significantly quieter than the same firearm shooting unsuppressed. But use a suppressor and use subsonic ammo, and you've eliminated the majority of noise that the firearm makes. The only remaining noise would be from the gun's action.

 

[ABTOMAT]

That's about right. Subsonic ammo will produce no sonic boom when fired, so if a supressor takes care of the muzzle blast it'll be pretty quiet.

(edit: whoops, got beaten to the punch.)

 

[Jenrick]

Depending on the caliber and the weapon it's intended for subsonic can be a good thing.

Certain suppresors are designed to be used w/ subsonic ammunition, and can be damaged by using supersonic rounds. I personally have no first hand experience with this, others can inform you more.

Secondly it's possible that a subsonic round can make the overall discharge of your weapon quieter since you won't have the snap/pop of the round going supersonic.

As you noted a lot of it is marketing. Some folks are all about a slower heavier round, rather then a lighter faster round. Saying a bullet is subsonic keys into that demographic. It is however normally used for rounds that do fall into that heavier category, so at least they're being truthful.

-Jenrick

 

[Aguila Blanca]

It is also argued that the sonic crack when the bullet transitions from subsonic to supersonic, and again when it drops out of being supersonic, destabilizes the bullet and that subsonic ammo is thus more accurate.

Why is it a "marketing trick" to label a product truthfully as to what it is? Why do you make a point of saying that "technically" any ammo with a velocity of less than the speed of sound is subsonic. That's not really so "technical." That's pretty much a matter of definition. It's either supersonic, or it's not.

If you don't want to buy sub-sonic ammo ... don't.

 

[Jim Watson]

It is not just supressor/silencers.
Muzzle blast is a component of felt recoil and a shot without the hard high-muzzle pressure blast and supersonic Crack! of a supersonic bullet is going to at least seem softer shooting. I find a 9mm 147 gr @ 900 fps to be milder to shoot than a 115 at 1150 even though the power factors are the same and the computed recoil the same or very close.