Just watched hickok45 run subsonic 9mm through an Uzi. I'm disappointed with myself I didn't even know it existed. I don't think I have ever heard subsonic discussed here.

 

Now discuss it and educate me. Why? Why not? Applications? (hd, range). Is it lethal?

It is lethal.

 

It is designed for use in conjunction with suppressors if I remember correctly, and I don't think it offers any advantages over standard 9mm without one.

 

Some of the suppressor guys (Midwest PX, Mipafox) should be able to chime in more.

Fiocchi 158 grain. Accept no substitute. It is so consistent, so clean that you don't need to clean your guns, so reliable, and the quietest stuff in mass production. Yes, no reason to buy unless you want to use with a can. The 158/9 slug was originally designed by the Israelis for the suppressed UZI.

 

DevAd, post your video of suppressed Fiocchi FA!

 

That being said, most 147 grain HP is subsonic by nature and might not be quite as quiet but makes nicer hole

Subsonic ammo is just designed not to break the sound barrier... no more, no less.

 

When a round (or anything) breaks the speed of sound, you'll hear a crack. This occurs around 1,150 feet per second, but varies due to location. If the round is going less than that, you won't have that crack. With suppressors, that means the only sound that needs to be suppressed is the actual gunshot... thus making it more effective. If you shoot ammo that breaks the sound barrier through a suppressor, it will be quieter... just still going to be loud with that crack.

 

Some rounds are designed to be subsonic, such as .300 Blackout (there are higher velocity loads, as well). Other rounds are just that way, such as common .45 ACP (slow and heavy bullet). If you want subsonic 9mm, look at 147 grain ammo. Usually, heavier rounds are used in subsonic applications, since weight is a very good braking system.

 

Benefit other than the lack of crack... not really. There are accuracy issues that come up when decelerating back across the sound barrier, but not going to be a big deal to most people. It really comes down to what you are looking for. Do you want a slow heavy bullet or a fast light one?

 

One spot where subsonic does come into play is .22 rifles... load .22 CB Longs, and you pretty much have a lethal BB gun report, if you must take out a pest (legally, of course).

I like to use 9mm 147 grain for competitions. It has a lighter recoil and makes for faster follow up shots.

I like to use 9mm 147 grain for competitions. It has a lighter recoil and makes for faster follow up shots.

I use it as well but I am not sure about your analysis.  You do indeed get less muzzle flip and that helps you get the sights back on target faster; But, I believe the slide also cycles slower which may actually negate some of that advantage.  I just like the way it feels.  Be careful for competition as I have seen some 147 offered recently that only makes 115 power factor.

Fiocchi 158 grain. Accept no substitute. It is so consistent, so clean that you don't need to clean your guns, so reliable, and the quietest stuff in mass production. Yes, no reason to buy unless you want to use with a can. The 158/9 slug was originally designed by the Israelis for the suppressed UZI.

 

DevAd, post your video of suppressed Fiocchi FA!

 

That being said, most 147 grain HP is subsonic by nature and might not be quite as quiet but makes nicer hole

 

If it's for an Uzi, why not use Israeli ammo?

http://www.sgammo.com/product/imi/50-round-box-9mm-luger-subsonic-158-grain-fmj-imi-ammo-made-israel-military-industries-m

http://www.sgammo.com/product/imi/1000-round-case-9mm-luger-subsonic-158-grain-fmj-imi-ammo-made-israel-military-industrie

Is there a noticeable decibel difference? No, I'm not asking if you don't need ear protection. I know that answer will be still needed.

If it's done right (and the can works right) the loudest sound you hear is the empty brass hitting the floor after the "PFFFFFFFFFFT".  Designed to eliminate threats very quietly, since the rounds never break Mach 1 (which FWIW is 1,050 FPS at sea level in Winter).  Used by elite forces & assassins the world over when you want to "get in and out" without being heard or putting-on a "Show".......

 

The laws of Physics still apply.  Heavier bullets tend to create MORE felt recoil, NOT less, provided all else (including bullet SPEED) is the same.....   This same heavier than normal bullet also makes-up for the loss of power (speed) to work the action in a semi-auto.  Some "tweaking" may be necessitated to receive flawless function as a result.

The difference isn't much.  It's only a few DB.

 

This shows only about 4DB difference without suppression. (Whiny voice kid warning)

https://www.youtube.com/watch?v=Ap86bXjg804 

https://youtu.be/U_yhqnfSjXA

 

 

The difference is vastly more significant with a 9mm hand gun.

I can tell you on an indoor concrete range, subsonic is much more fun to shoot lots of than supersonic. it makes a difference, suppressor or not.

I can tell you on an indoor concrete range, subsonic is much more fun to shoot lots of than supersonic. it makes a difference, suppressor or not.

I've had many people ask me what I am shooting when I shoot indoor matches as it definitely has a different sound than typical 115 or 124 grain ammo due to it being subsonic

Someone just remind me quick for 9mm only. (Not 223). Which would have more over penetration risk? The fast 115 or the slow 147?

 

Talking HD scenario?

 

Yes of course make sure it cycles your gun.

Depends on the head of the pill.  FMJ have a tendency to travel farther that HP.  

I see this conversation has turned towards "normal' (not "CB" or purpose built .22rf subsonic) ammo used unsuppressed. Never gave it much thought but the answers I am reading here make sense. Two simple examples.

 

A well suppressed 5.56 round is louder than an unsupressed .22. So, obviously that sonic crack counts quite a bit.

 

Another one. Normal HV .22 LR ammo fired from a handgun is subsonic. Doesn't hurt my ears. Fired from a rifle, it is supersonic, and much louder.

 

So that crack seems to contribute sound roughly in the same ballpark of the noise from a .22. Depending on the projectile of course, an F-15 will break my windows with the sonic boom whereas a 5.56 will not

 

Odd thing is, when I have had bullets go by me, the crack never seemed all that loud. But that may have been due in part to temporary hearing loss and being focused on other things.

I find that most 9mm ammo shoots subsonic anyway out of 4inch barrels and get just below at 5 and is just over at 6". My hand loads are 124gr at 1050fps out of a 5" barrel.

115gr American Eagle 9mm FMJ Averaged out at 1128 FPS.  Speed of sound @ sea level is 1125 FPS...  Right on the cusp.

 

Interesting I was getting about 1050fps out of my px4 compact using Federal AE 115gr

 

Nevermind I just remembered the barrel is 3.3" so at 4" you would be touching super sonic.

Subsonic ammo is generally used strictly with suppressors. Suppressors are illegal in NJ, so not much talk about subsonic ammo.

 

Except for .45 ACP , which is naturally subsonic