Suppressors Sub sonic without can?

GillJr

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Dec 11, 2009
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I have looked and looked but can't find a video of sub sonic comparsion to super sonic 308. I just curious what is the noise level difference. Anyone have a vid or know where one is? Or give me there personnal opinion.
 
Re: Sub sonic without can?

If you are talking about unsuppressed, my guess is all you would lose is the supersonic "crack" - with rimfires it is difficult for me to tell the difference. 45 ACP is subsonic, and it isn't quiet. When shooting suppressed, there is a notable difference between subsonic and supersonic.
 
Re: Sub sonic without can?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GillJr</div><div class="ubbcode-body">Was wondering if their was any noise reduction and I guess not. Thanks Guys </div></div>

Yes, there is major noise reduction over a full power load.
Different barrel lengths and powder combo's will produce different results. A can works the best, but you can get quality results without one, especially if your using a 22lr. Custom 22lr barrels can be had to whatever length you want. I have found with certain 22 sub ammo once you get to 27" a can is a waste of money.
Then again us Hill-Billys have always been penny pinch'ers.
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Re: Sub sonic without can?

A buddy of mine was shooting subsonic loads out of an unsuppressed semi-auto 308 not to long ago and it was much quieter than my full power 308 loads, but it was not suppressor quiet.
 
Re: Sub sonic without can?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: head2h2o</div><div class="ubbcode-body">A buddy of mine was shooting subsonic loads out of an unsuppressed semi-auto 308 not to long ago and it was much quieter than my full power 308 loads, but it was not suppressor quiet. </div></div>

^^^^this, I have shot SS rounds out of my .308 a couple times just to see what they sound like. Much quieter than full house loads, but still too loud for no protection, to my half-deaf untrained ears it sounded just like a 9mm.
 
Re: Sub sonic without can?

I'm not sure the OP has a good concept of what a suppressor does.

Have you ever opened a champagne bottle? Because there is pressure inside the bottle, when you open the bottle, the pressure gets vented to the atmosphere, and you hear a pop.

Guns work the same way. It takes pressure to push the bullet out of the barrel, and after the bullet leaves the barrel, the pressure is vented to the atmosphere and there is a pop.

If the bullet is traveling above the speed of sound, there is an additional sound - the supersonic crack that follows the bullet through its trajectory.

So you're going to get the pop either way - whether your bullet is subsonic or supersonic. Suppressors lessen the pop. They do nothing for the bullet flight noise.

All things being equal (and they seldom are), a subsonic round will generally have less pressure to vent to the atmosphere than a supersonic round. So the subsonic round's pop will be less than the supersonic round's pop. But it'll probably still be loud enough to damage your hearing.

Suppressors used with subsonic ammo yield a very small sound signature. The suppressor mostly contains the pop and there is little or no bullet flight noise.

Suppressors used with supersonic yield a sound level to the shooter that is hopefully hearing safe, based on the suppression level of the can. But others standing to the side or in front of the suppressor will experience MUCH more sound than the shooter behind the can. And the bullet will scream past them.

Observations: .22lr is generally quieter through rifle than through a pistol. With a pistol's short barrel, the pressure that gets released to the atmosphere is greater. With a rifle's long barrel, the pressure that gets released to the atmosphere is less. But...often .22lr high velocity ammo is subsonic through a pistol while the same ammo is supersonic through a rifle.

While .45acp is subsonic, .45 pistols are pretty loud. Shoot that same .45acp round through a rifle with a 16" or longer barrel and it will not be nearly as loud.
 
Re: Sub sonic without can?

I have a 300 Blackout that I have been shooting unsuppressed. I have fired it a few times without hearing protection (intentionally, stupid, I know...) and found the loud pop to be unpleasant but do-able. Not so with a 308 or even a .223.

Don't discount how loud that supersonic crack can be! On my last trip to the Whittington Center my buddy was in the pit while I was on the 1000 yard line. He didn't have hearing protection in when I fired and said the round passing overhead (338 Lap.) "sounded like a stick of dynamite."
 
Re: Sub sonic without can?

We shoot subsonic 308 (180 gn sierra RN trail boss). And in 20 inch barrel it is very quiet. I made a huge mistake and cut the barrel to 16.5 and installed a two chamber brake, now it is obnoxiously loud.

In my 24 " barrel with an FTE it is pretty quiet as well. I consider it to be a little louder than a 22lr. I can comfortably shoot it without ears.
 
Re: Sub sonic without can?

Colt, the primary pop is made when the static air captured in front of the projectile is forced into the open atmosphere. The secondary is when the propellant gases can finally escape from behind the projectile and go ss, the last phase is when the projectile achieves ss flight. Yes, there are suppressors that can and do effect the projectile's ss noise, they are called integrals.

An unsupressed .30 fast enough to make it out of a 20" barrel is "very quiet." A subsonic .30 making it out of a 24" barrel and having the residuals cast back with an FTE is "pretty quiet" as well. I don't think so. Time for a hearing test. Subsonic .22 cause hearing damage. Most I have measured come in at 125-130 dB, more than enough to cause damage.

http://www.pegasusrotorcraft.com/supportdocuments/SoundRatings.pdf

 
Re: Sub sonic without can?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RollingThunder51</div><div class="ubbcode-body">Yes, there are suppressors that can and do effect the projectile's ss noise, they are called integrals.
</div></div>

Integral suppressors, with ported barrels (like an MP5-SD, various .22lr designs, 77/44, etc.), have ported barrels, which bleed off pressure and result in the projectile leaving the barrel below the speed of sound. Thus you get subsonic projectile speed without having to use subsonic ammunition. In the aforementioned MP5-SD, this equates to .380 ballistics from 9mm ammo.
 
Re: Sub sonic without can?

With my 300 blackout subsonics it's about like shooting a 9mm pistol. Plenty loud, need muffs or your ears will ring. It is noticeably quieter than a full powered 308 load though, and as it should be since it's going 1/3 of the velocity and uses 1/4 of the powder.
 
Re: Sub sonic without can?

I agree for sustained firing ears are mandatory, but if I were to take a shot or two at a critter it is not uncomfortable or excessively loud. It is definitely much quieter than supersonics! (and a shit pile of fun to boot, I say give them a try if you are a hand loader!)
 
Re: Sub sonic without can?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RollingThunder51</div><div class="ubbcode-body">Better. My point was that "They do nothing for the bullet flight noise" is incorrect. </div></div>

I believe you interpreted my statement out of the context that I meant it to be in - meaning that the suppressor can do nothing once the projectile is gone. I stand by this statement. While the bullet has cleared the suppressor and is flying down range (and this is when it generates bullet flight noise) the silencer can do nothing for it. This is my point.