SBR and Sub Sonic


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dscottw88
September 13, 2007, 05:02 PM
First off, forgive my ignorances, I don't know too much about SBRs or Sub Sonic ammunition. I plan on buying an SBR in 9mm, and am aware of registering it with the ATF. What I want to know is If I was also interested in Registering a suppressor with the ATF, would I need to look into buying sub sonic ammunition? Does grain make a difference when applied to sub sonic ammunition? How fast is sub sonic ammunition roughly? And lastly, would a suppressor increase residue build up?

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Correia
September 13, 2007, 05:15 PM
The supersonic noise of the bullet is not that bad. You do not need to shoot subsonic through a suppressor.

It is quieter, but the vast majority of the noise you hear as the shooter is muzzle blast. I've got a couple of suppressed guns, and I shoot regular factory ammo the vast majority of the time.

Now don't worry, somebody who has never shot a suppressed weapon will be along shortly to warn you about the "devestating" supersonic crack. :)

Hkmp5sd
September 13, 2007, 08:37 PM
Depending on the gun, you will be surprised how much noise the bolt makes when moving.

MisterPX
September 13, 2007, 11:24 PM
In 9mm, subsonics and a good can is a world of difference against supersonic. Subs can get you to "hollywood quiet".

dscottw88
September 14, 2007, 01:12 AM
HK style bolt, same used in the MP5 platform.

Hkmp5sd
September 14, 2007, 02:27 AM
If you happen to have this platform, you don't need to worry about supersonic rounds. The barrel is perforated to slow the bullet down to subsonic speeds. The bolt is pretty quiet too. :)

http://img.photobucket.com/albums/v495/Hkmp5sd/HKMP5SD.jpg?t=1189747226

Lucky
September 14, 2007, 03:46 AM
Pulling targets or playing with a bull-whip, supersonic cracks hurt my ears. My basic understanding of the effect, with the overlapping, expanding bubbles, makes me wonder if the shooter is really hearing the supersonic crack or just an echo of it off something. Don't see how it can travel backwards, seems it should only travel laterally.

dscottw88
September 14, 2007, 05:36 AM
The MP5 Rifle i'm talking about is more of a mix between an MP5 and UMP9mm. This rifle looks really promising! This short video pretty much speaks for the gun itself! http://www.youtube.com/watch?v=fe0mwGjfYa0&mode=related&search=

Bartholomew Roberts
September 14, 2007, 09:08 AM
My basic understanding of the effect, with the overlapping, expanding bubbles, makes me wonder if the shooter is really hearing the supersonic crack or just an echo of it off something.

Probably the echo. I know with my can, it makes an odd sound on U-shaped berms as you can hear the crack echo back off the side berms as it travels downrange. The sound is kind of a cross between a miniature train travelling downrange and an air wrench in a shop. On open ranges with just a single berm downrange, it makes a different noise entirely and it is quiet enough you can hear the THWAP! of the bullet hitting the backstop.

MaterDei
September 14, 2007, 09:17 AM
I'm interested in hearing more about the 9mm SBR you're interested in. SBRs, in addition to the tax, come with other restrictions as well. Have you considered other options such as an AR or AK pistol? The AR pistol can be 9mm.

Just curious.

EDIT: Oops, I didn't realize that you were the one who posted the video link. How long is the barrel on that gun? Are you sure it is an SBR?

Hkmp5sd
September 14, 2007, 09:49 AM
How long is the barrel on that gun? Are you sure it is an SBR?


The one in the video is an MP5 clone which has a 9" barrel. The company also manufactures a semi-auto version with a 16" barrel.

SBRs, in addition to the tax, come with other restrictions as well.

Other than being an NFA item, what restrictions?

MisterPX
September 14, 2007, 06:17 PM
Only downside I can think of with a SBR is filing a 5320 to travel interstate.

W.E.G.
September 14, 2007, 06:23 PM
Be very careful about subsonic ammo through suppressors.

Be absolutely certain that your rifling twist-rate is correct for the (usually much heavier than normal) subsonic bullets.

Otherwise you will have baffle-strikes in the suppresor.

Even if the suppressor is not completely destroyed, it is very expensive to replace the baffle stack.
Ask me how I know. :(

dscottw88
September 14, 2007, 08:15 PM
To MasterDei: The company's main page is here. http://www.professional-arms.com/ It was stated that they have a 9 and 16 inch barrel for this model, but i'm only interested in it because with the SBR i have an option to throw in a suppressor. I simply think it would be a blast! Who doesn't wanna shoot essentially a Silenced MP5? Haha, thanks for the help guys!

W.E.G: So the subsonic rounds are much higher grain? what kind of twist rate would I want??? Is there a downside to having a barrel with a higher twist rate if I take off the suppressor and fire average practice ammo? now i'm worried.

MisterPX
September 15, 2007, 01:18 PM
I've never had any issues with 147 gr loads though any of my pistol/sbr-can combinations.

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